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42<h1 class="settitle">Installing GCC: Configuration</h1>
43<a name="index-Configuration-1"></a><a name="index-Installing-GCC_003a-Configuration-2"></a>
44Like most GNU software, GCC must be configured before it can be built. 
45This document describes the recommended configuration procedure
46for both native and cross targets.
47
48   <p>We use <var>srcdir</var> to refer to the toplevel source directory for
49GCC; we use <var>objdir</var> to refer to the toplevel build/object directory.
50
51   <p>If you obtained the sources via SVN, <var>srcdir</var> must refer to the top
52<samp><span class="file">gcc</span></samp> directory, the one where the <samp><span class="file">MAINTAINERS</span></samp> file can be
53found, and not its <samp><span class="file">gcc</span></samp> subdirectory, otherwise the build will fail.
54
55   <p>If either <var>srcdir</var> or <var>objdir</var> is located on an automounted NFS
56file system, the shell's built-in <samp><span class="command">pwd</span></samp> command will return
57temporary pathnames.  Using these can lead to various sorts of build
58problems.  To avoid this issue, set the <samp><span class="env">PWDCMD</span></samp> environment
59variable to an automounter-aware <samp><span class="command">pwd</span></samp> command, e.g.,
60<samp><span class="command">pawd</span></samp> or &lsquo;<samp><span class="samp">amq -w</span></samp>&rsquo;, during the configuration and build
61phases.
62
63   <p>First, we <strong>highly</strong> recommend that GCC be built into a
64separate directory from the sources which does <strong>not</strong> reside
65within the source tree.  This is how we generally build GCC; building
66where <var>srcdir</var> == <var>objdir</var> should still work, but doesn't
67get extensive testing; building where <var>objdir</var> is a subdirectory
68of <var>srcdir</var> is unsupported.
69
70   <p>If you have previously built GCC in the same directory for a
71different target machine, do &lsquo;<samp><span class="samp">make distclean</span></samp>&rsquo; to delete all files
72that might be invalid.  One of the files this deletes is <samp><span class="file">Makefile</span></samp>;
73if &lsquo;<samp><span class="samp">make distclean</span></samp>&rsquo; complains that <samp><span class="file">Makefile</span></samp> does not exist
74or issues a message like &ldquo;don't know how to make distclean&rdquo; it probably
75means that the directory is already suitably clean.  However, with the
76recommended method of building in a separate <var>objdir</var>, you should
77simply use a different <var>objdir</var> for each target.
78
79   <p>Second, when configuring a native system, either <samp><span class="command">cc</span></samp> or
80<samp><span class="command">gcc</span></samp> must be in your path or you must set <samp><span class="env">CC</span></samp> in
81your environment before running configure.  Otherwise the configuration
82scripts may fail.
83
84   <p>To configure GCC:
85
86<pre class="smallexample">     % mkdir <var>objdir</var>
87     % cd <var>objdir</var>
88     % <var>srcdir</var>/configure [<var>options</var>] [<var>target</var>]
89</pre>
90   <h3 class="heading"><a name="TOC0"></a>Distributor options</h3>
91
92<p>If you will be distributing binary versions of GCC, with modifications
93to the source code, you should use the options described in this
94section to make clear that your version contains modifications.
95
96     <dl>
97<dt><code>--with-pkgversion=</code><var>version</var><dd>Specify a string that identifies your package.  You may wish
98to include a build number or build date.  This version string will be
99included in the output of <samp><span class="command">gcc --version</span></samp>.  This suffix does
100not replace the default version string, only the &lsquo;<samp><span class="samp">GCC</span></samp>&rsquo; part.
101
102     <p>The default value is &lsquo;<samp><span class="samp">GCC</span></samp>&rsquo;.
103
104     <br><dt><code>--with-bugurl=</code><var>url</var><dd>Specify the URL that users should visit if they wish to report a bug. 
105You are of course welcome to forward bugs reported to you to the FSF,
106if you determine that they are not bugs in your modifications.
107
108     <p>The default value refers to the FSF's GCC bug tracker.
109
110   </dl>
111
112<h3 class="heading"><a name="TOC1"></a>Target specification</h3>
113
114     <ul>
115<li>GCC has code to correctly determine the correct value for <var>target</var>
116for nearly all native systems.  Therefore, we highly recommend you do
117not provide a configure target when configuring a native compiler.
118
119     <li><var>target</var> must be specified as <samp><span class="option">--target=</span><var>target</var></samp>
120when configuring a cross compiler; examples of valid targets would be
121m68k-elf, sh-elf, etc.
122
123     <li>Specifying just <var>target</var> instead of <samp><span class="option">--target=</span><var>target</var></samp>
124implies that the host defaults to <var>target</var>. 
125</ul>
126
127<h3 class="heading"><a name="TOC2"></a>Options specification</h3>
128
129<p>Use <var>options</var> to override several configure time options for
130GCC.  A list of supported <var>options</var> follows; &lsquo;<samp><span class="samp">configure
131--help</span></samp>&rsquo; may list other options, but those not listed below may not
132work and should not normally be used.
133
134   <p>Note that each <samp><span class="option">--enable</span></samp> option has a corresponding
135<samp><span class="option">--disable</span></samp> option and that each <samp><span class="option">--with</span></samp> option has a
136corresponding <samp><span class="option">--without</span></samp> option.
137
138     <dl>
139<dt><code>--prefix=</code><var>dirname</var><dd>Specify the toplevel installation
140directory.  This is the recommended way to install the tools into a directory
141other than the default.  The toplevel installation directory defaults to
142<samp><span class="file">/usr/local</span></samp>.
143
144     <p>We <strong>highly</strong> recommend against <var>dirname</var> being the same or a
145subdirectory of <var>objdir</var> or vice versa.  If specifying a directory
146beneath a user's home directory tree, some shells will not expand
147<var>dirname</var> correctly if it contains the &lsquo;<samp><span class="samp">~</span></samp>&rsquo; metacharacter; use
148<samp><span class="env">$HOME</span></samp> instead.
149
150     <p>The following standard <samp><span class="command">autoconf</span></samp> options are supported.  Normally you
151should not need to use these options.
152          <dl>
153<dt><code>--exec-prefix=</code><var>dirname</var><dd>Specify the toplevel installation directory for architecture-dependent
154files.  The default is <samp><var>prefix</var></samp>.
155
156          <br><dt><code>--bindir=</code><var>dirname</var><dd>Specify the installation directory for the executables called by users
157(such as <samp><span class="command">gcc</span></samp> and <samp><span class="command">g++</span></samp>).  The default is
158<samp><var>exec-prefix</var><span class="file">/bin</span></samp>.
159
160          <br><dt><code>--libdir=</code><var>dirname</var><dd>Specify the installation directory for object code libraries and
161internal data files of GCC.  The default is <samp><var>exec-prefix</var><span class="file">/lib</span></samp>.
162
163          <br><dt><code>--libexecdir=</code><var>dirname</var><dd>Specify the installation directory for internal executables of GCC. 
164The default is <samp><var>exec-prefix</var><span class="file">/libexec</span></samp>.
165
166          <br><dt><code>--with-slibdir=</code><var>dirname</var><dd>Specify the installation directory for the shared libgcc library.  The
167default is <samp><var>libdir</var></samp>.
168
169          <br><dt><code>--datarootdir=</code><var>dirname</var><dd>Specify the root of the directory tree for read-only architecture-independent
170data files referenced by GCC.  The default is <samp><var>prefix</var><span class="file">/share</span></samp>.
171
172          <br><dt><code>--infodir=</code><var>dirname</var><dd>Specify the installation directory for documentation in info format. 
173The default is <samp><var>datarootdir</var><span class="file">/info</span></samp>.
174
175          <br><dt><code>--datadir=</code><var>dirname</var><dd>Specify the installation directory for some architecture-independent
176data files referenced by GCC.  The default is <samp><var>datarootdir</var></samp>.
177
178          <br><dt><code>--docdir=</code><var>dirname</var><dd>Specify the installation directory for documentation files (other
179than Info) for GCC.  The default is <samp><var>datarootdir</var><span class="file">/doc</span></samp>.
180
181          <br><dt><code>--htmldir=</code><var>dirname</var><dd>Specify the installation directory for HTML documentation files. 
182The default is <samp><var>docdir</var></samp>.
183
184          <br><dt><code>--pdfdir=</code><var>dirname</var><dd>Specify the installation directory for PDF documentation files. 
185The default is <samp><var>docdir</var></samp>.
186
187          <br><dt><code>--mandir=</code><var>dirname</var><dd>Specify the installation directory for manual pages.  The default is
188<samp><var>datarootdir</var><span class="file">/man</span></samp>.  (Note that the manual pages are only extracts
189from the full GCC manuals, which are provided in Texinfo format.  The manpages
190are derived by an automatic conversion process from parts of the full
191manual.)
192
193          <br><dt><code>--with-gxx-include-dir=</code><var>dirname</var><dd>Specify
194the installation directory for G++ header files.  The default depends
195on other configuration options, and differs between cross and native
196configurations.
197
198          <br><dt><code>--with-specs=</code><var>specs</var><dd>Specify additional command line driver SPECS. 
199This can be useful if you need to turn on a non-standard feature by
200default without modifying the compiler's source code, for instance
201<samp><span class="option">--with-specs=%{!fcommon:%{!fno-common:-fno-common}}</span></samp>. 
202See &ldquo;Spec Files&rdquo; in the main manual
203
204     </dl>
205
206     <br><dt><code>--program-prefix=</code><var>prefix</var><dd>GCC supports some transformations of the names of its programs when
207installing them.  This option prepends <var>prefix</var> to the names of
208programs to install in <var>bindir</var> (see above).  For example, specifying
209<samp><span class="option">--program-prefix=foo-</span></samp> would result in &lsquo;<samp><span class="samp">gcc</span></samp>&rsquo;
210being installed as <samp><span class="file">/usr/local/bin/foo-gcc</span></samp>.
211
212     <br><dt><code>--program-suffix=</code><var>suffix</var><dd>Appends <var>suffix</var> to the names of programs to install in <var>bindir</var>
213(see above).  For example, specifying <samp><span class="option">--program-suffix=-3.1</span></samp>
214would result in &lsquo;<samp><span class="samp">gcc</span></samp>&rsquo; being installed as
215<samp><span class="file">/usr/local/bin/gcc-3.1</span></samp>.
216
217     <br><dt><code>--program-transform-name=</code><var>pattern</var><dd>Applies the &lsquo;<samp><span class="samp">sed</span></samp>&rsquo; script <var>pattern</var> to be applied to the names
218of programs to install in <var>bindir</var> (see above).  <var>pattern</var> has to
219consist of one or more basic &lsquo;<samp><span class="samp">sed</span></samp>&rsquo; editing commands, separated by
220semicolons.  For example, if you want the &lsquo;<samp><span class="samp">gcc</span></samp>&rsquo; program name to be
221transformed to the installed program <samp><span class="file">/usr/local/bin/myowngcc</span></samp> and
222the &lsquo;<samp><span class="samp">g++</span></samp>&rsquo; program name to be transformed to
223<samp><span class="file">/usr/local/bin/gspecial++</span></samp> without changing other program names,
224you could use the pattern
225<samp><span class="option">--program-transform-name='s/^gcc$/myowngcc/; s/^g++$/gspecial++/'</span></samp>
226to achieve this effect.
227
228     <p>All three options can be combined and used together, resulting in more
229complex conversion patterns.  As a basic rule, <var>prefix</var> (and
230<var>suffix</var>) are prepended (appended) before further transformations
231can happen with a special transformation script <var>pattern</var>.
232
233     <p>As currently implemented, this option only takes effect for native
234builds; cross compiler binaries' names are not transformed even when a
235transformation is explicitly asked for by one of these options.
236
237     <p>For native builds, some of the installed programs are also installed
238with the target alias in front of their name, as in
239&lsquo;<samp><span class="samp">i686-pc-linux-gnu-gcc</span></samp>&rsquo;.  All of the above transformations happen
240before the target alias is prepended to the name&mdash;so, specifying
241<samp><span class="option">--program-prefix=foo-</span></samp> and <samp><span class="option">program-suffix=-3.1</span></samp>, the
242resulting binary would be installed as
243<samp><span class="file">/usr/local/bin/i686-pc-linux-gnu-foo-gcc-3.1</span></samp>.
244
245     <p>As a last shortcoming, none of the installed Ada programs are
246transformed yet, which will be fixed in some time.
247
248     <br><dt><code>--with-local-prefix=</code><var>dirname</var><dd>Specify the
249installation directory for local include files.  The default is
250<samp><span class="file">/usr/local</span></samp>.  Specify this option if you want the compiler to
251search directory <samp><var>dirname</var><span class="file">/include</span></samp> for locally installed
252header files <em>instead</em> of <samp><span class="file">/usr/local/include</span></samp>.
253
254     <p>You should specify <samp><span class="option">--with-local-prefix</span></samp> <strong>only</strong> if your
255site has a different convention (not <samp><span class="file">/usr/local</span></samp>) for where to put
256site-specific files.
257
258     <p>The default value for <samp><span class="option">--with-local-prefix</span></samp> is <samp><span class="file">/usr/local</span></samp>
259regardless of the value of <samp><span class="option">--prefix</span></samp>.  Specifying
260<samp><span class="option">--prefix</span></samp> has no effect on which directory GCC searches for
261local header files.  This may seem counterintuitive, but actually it is
262logical.
263
264     <p>The purpose of <samp><span class="option">--prefix</span></samp> is to specify where to <em>install
265GCC</em>.  The local header files in <samp><span class="file">/usr/local/include</span></samp>&mdash;if you put
266any in that directory&mdash;are not part of GCC.  They are part of other
267programs&mdash;perhaps many others.  (GCC installs its own header files in
268another directory which is based on the <samp><span class="option">--prefix</span></samp> value.)
269
270     <p>Both the local-prefix include directory and the GCC-prefix include
271directory are part of GCC's &ldquo;system include&rdquo; directories.  Although these
272two directories are not fixed, they need to be searched in the proper
273order for the correct processing of the include_next directive.  The
274local-prefix include directory is searched before the GCC-prefix
275include directory.  Another characteristic of system include directories
276is that pedantic warnings are turned off for headers in these directories.
277
278     <p>Some autoconf macros add <samp><span class="option">-I </span><var>directory</var></samp> options to the
279compiler command line, to ensure that directories containing installed
280packages' headers are searched.  When <var>directory</var> is one of GCC's
281system include directories, GCC will ignore the option so that system
282directories continue to be processed in the correct order.  This
283may result in a search order different from what was specified but the
284directory will still be searched.
285
286     <p>GCC automatically searches for ordinary libraries using
287<samp><span class="env">GCC_EXEC_PREFIX</span></samp>.  Thus, when the same installation prefix is
288used for both GCC and packages, GCC will automatically search for
289both headers and libraries.  This provides a configuration that is
290easy to use.  GCC behaves in a manner similar to that when it is
291installed as a system compiler in <samp><span class="file">/usr</span></samp>.
292
293     <p>Sites that need to install multiple versions of GCC may not want to
294use the above simple configuration.  It is possible to use the
295<samp><span class="option">--program-prefix</span></samp>, <samp><span class="option">--program-suffix</span></samp> and
296<samp><span class="option">--program-transform-name</span></samp> options to install multiple versions
297into a single directory, but it may be simpler to use different prefixes
298and the <samp><span class="option">--with-local-prefix</span></samp> option to specify the location of the
299site-specific files for each version.  It will then be necessary for
300users to specify explicitly the location of local site libraries
301(e.g., with <samp><span class="env">LIBRARY_PATH</span></samp>).
302
303     <p>The same value can be used for both <samp><span class="option">--with-local-prefix</span></samp> and
304<samp><span class="option">--prefix</span></samp> provided it is not <samp><span class="file">/usr</span></samp>.  This can be used
305to avoid the default search of <samp><span class="file">/usr/local/include</span></samp>.
306
307     <p><strong>Do not</strong> specify <samp><span class="file">/usr</span></samp> as the <samp><span class="option">--with-local-prefix</span></samp>! 
308The directory you use for <samp><span class="option">--with-local-prefix</span></samp> <strong>must not</strong>
309contain any of the system's standard header files.  If it did contain
310them, certain programs would be miscompiled (including GNU Emacs, on
311certain targets), because this would override and nullify the header
312file corrections made by the <samp><span class="command">fixincludes</span></samp> script.
313
314     <p>Indications are that people who use this option use it based on mistaken
315ideas of what it is for.  People use it as if it specified where to
316install part of GCC.  Perhaps they make this assumption because
317installing GCC creates the directory.
318
319     <br><dt><code>--with-native-system-header-dir=</code><var>dirname</var><dd>Specifies that <var>dirname</var> is the directory that contains native system
320header files, rather than <samp><span class="file">/usr/include</span></samp>.  This option is most useful
321if you are creating a compiler that should be isolated from the system
322as much as possible.  It is most commonly used with the
323<samp><span class="option">--with-sysroot</span></samp> option and will cause GCC to search
324<var>dirname</var> inside the system root specified by that option.
325
326     <br><dt><code>--enable-shared[=</code><var>package</var><code>[,...]]</code><dd>Build shared versions of libraries, if shared libraries are supported on
327the target platform.  Unlike GCC 2.95.x and earlier, shared libraries
328are enabled by default on all platforms that support shared libraries.
329
330     <p>If a list of packages is given as an argument, build shared libraries
331only for the listed packages.  For other packages, only static libraries
332will be built.  Package names currently recognized in the GCC tree are
333&lsquo;<samp><span class="samp">libgcc</span></samp>&rsquo; (also known as &lsquo;<samp><span class="samp">gcc</span></samp>&rsquo;), &lsquo;<samp><span class="samp">libstdc++</span></samp>&rsquo; (not
334&lsquo;<samp><span class="samp">libstdc++-v3</span></samp>&rsquo;), &lsquo;<samp><span class="samp">libffi</span></samp>&rsquo;, &lsquo;<samp><span class="samp">zlib</span></samp>&rsquo;, &lsquo;<samp><span class="samp">boehm-gc</span></samp>&rsquo;,
335&lsquo;<samp><span class="samp">ada</span></samp>&rsquo;, &lsquo;<samp><span class="samp">libada</span></samp>&rsquo;, &lsquo;<samp><span class="samp">libjava</span></samp>&rsquo;, &lsquo;<samp><span class="samp">libgo</span></samp>&rsquo;, and &lsquo;<samp><span class="samp">libobjc</span></samp>&rsquo;. 
336Note &lsquo;<samp><span class="samp">libiberty</span></samp>&rsquo; does not support shared libraries at all.
337
338     <p>Use <samp><span class="option">--disable-shared</span></samp> to build only static libraries.  Note that
339<samp><span class="option">--disable-shared</span></samp> does not accept a list of package names as
340argument, only <samp><span class="option">--enable-shared</span></samp> does.
341
342     <p>Contrast with <samp><span class="option">--enable-host-shared</span></samp>, which affects <em>host</em>
343code.
344
345     <br><dt><code>--enable-host-shared</code><dd>Specify that the <em>host</em> code should be built into position-independent
346machine code (with -fPIC), allowing it to be used within shared libraries,
347but yielding a slightly slower compiler.
348
349     <p>This option is required when building the libgccjit.so library.
350
351     <p>Contrast with <samp><span class="option">--enable-shared</span></samp>, which affects <em>target</em>
352libraries.
353
354     <br><dt><code><a name="with_002dgnu_002das"></a>--with-gnu-as</code><dd>Specify that the compiler should assume that the
355assembler it finds is the GNU assembler.  However, this does not modify
356the rules to find an assembler and will result in confusion if the
357assembler found is not actually the GNU assembler.  (Confusion may also
358result if the compiler finds the GNU assembler but has not been
359configured with <samp><span class="option">--with-gnu-as</span></samp>.)  If you have more than one
360assembler installed on your system, you may want to use this option in
361connection with <samp><span class="option">--with-as=</span><var>pathname</var></samp> or
362<samp><span class="option">--with-build-time-tools=</span><var>pathname</var></samp>.
363
364     <p>The following systems are the only ones where it makes a difference
365whether you use the GNU assembler.  On any other system,
366<samp><span class="option">--with-gnu-as</span></samp> has no effect.
367
368          <ul>
369<li>&lsquo;<samp><span class="samp">hppa1.0-</span><var>any</var><span class="samp">-</span><var>any</var></samp>&rsquo;
370<li>&lsquo;<samp><span class="samp">hppa1.1-</span><var>any</var><span class="samp">-</span><var>any</var></samp>&rsquo;
371<li>&lsquo;<samp><span class="samp">sparc-sun-solaris2.</span><var>any</var></samp>&rsquo;
372<li>&lsquo;<samp><span class="samp">sparc64-</span><var>any</var><span class="samp">-solaris2.</span><var>any</var></samp>&rsquo;
373</ul>
374
375     <br><dt><code><a name="with_002das"></a>--with-as=</code><var>pathname</var><dd>Specify that the compiler should use the assembler pointed to by
376<var>pathname</var>, rather than the one found by the standard rules to find
377an assembler, which are:
378          <ul>
379<li>Unless GCC is being built with a cross compiler, check the
380<samp><var>libexec</var><span class="file">/gcc/</span><var>target</var><span class="file">/</span><var>version</var></samp> directory. 
381<var>libexec</var> defaults to <samp><var>exec-prefix</var><span class="file">/libexec</span></samp>;
382<var>exec-prefix</var> defaults to <var>prefix</var>, which
383defaults to <samp><span class="file">/usr/local</span></samp> unless overridden by the
384<samp><span class="option">--prefix=</span><var>pathname</var></samp> switch described above.  <var>target</var>
385is the target system triple, such as &lsquo;<samp><span class="samp">sparc-sun-solaris2.7</span></samp>&rsquo;, and
386<var>version</var> denotes the GCC version, such as 3.0.
387
388          <li>If the target system is the same that you are building on, check
389operating system specific directories (e.g. <samp><span class="file">/usr/ccs/bin</span></samp> on
390Sun Solaris 2).
391
392          <li>Check in the <samp><span class="env">PATH</span></samp> for a tool whose name is prefixed by the
393target system triple.
394
395          <li>Check in the <samp><span class="env">PATH</span></samp> for a tool whose name is not prefixed by the
396target system triple, if the host and target system triple are
397the same (in other words, we use a host tool if it can be used for
398the target as well). 
399</ul>
400
401     <p>You may want to use <samp><span class="option">--with-as</span></samp> if no assembler
402is installed in the directories listed above, or if you have multiple
403assemblers installed and want to choose one that is not found by the
404above rules.
405
406     <br><dt><code><a name="with_002dgnu_002dld"></a>--with-gnu-ld</code><dd>Same as <a href="#with-gnu-as"><samp><span class="option">--with-gnu-as</span></samp></a>
407but for the linker.
408
409     <br><dt><code>--with-ld=</code><var>pathname</var><dd>Same as <a href="#with-as"><samp><span class="option">--with-as</span></samp></a>
410but for the linker.
411
412     <br><dt><code>--with-stabs</code><dd>Specify that stabs debugging
413information should be used instead of whatever format the host normally
414uses.  Normally GCC uses the same debug format as the host system.
415
416     <p>On MIPS based systems and on Alphas, you must specify whether you want
417GCC to create the normal ECOFF debugging format, or to use BSD-style
418stabs passed through the ECOFF symbol table.  The normal ECOFF debug
419format cannot fully handle languages other than C.  BSD stabs format can
420handle other languages, but it only works with the GNU debugger GDB.
421
422     <p>Normally, GCC uses the ECOFF debugging format by default; if you
423prefer BSD stabs, specify <samp><span class="option">--with-stabs</span></samp> when you configure GCC.
424
425     <p>No matter which default you choose when you configure GCC, the user
426can use the <samp><span class="option">-gcoff</span></samp> and <samp><span class="option">-gstabs+</span></samp> options to specify explicitly
427the debug format for a particular compilation.
428
429     <p><samp><span class="option">--with-stabs</span></samp> is meaningful on the ISC system on the 386, also, if
430<samp><span class="option">--with-gas</span></samp> is used.  It selects use of stabs debugging
431information embedded in COFF output.  This kind of debugging information
432supports C++ well; ordinary COFF debugging information does not.
433
434     <p><samp><span class="option">--with-stabs</span></samp> is also meaningful on 386 systems running SVR4.  It
435selects use of stabs debugging information embedded in ELF output.  The
436C++ compiler currently (2.6.0) does not support the DWARF debugging
437information normally used on 386 SVR4 platforms; stabs provide a
438workable alternative.  This requires gas and gdb, as the normal SVR4
439tools can not generate or interpret stabs.
440
441     <br><dt><code>--with-tls=</code><var>dialect</var><dd>Specify the default TLS dialect, for systems were there is a choice. 
442For ARM targets, possible values for <var>dialect</var> are <code>gnu</code> or
443<code>gnu2</code>, which select between the original GNU dialect and the GNU TLS
444descriptor-based dialect.
445
446     <br><dt><code>--enable-multiarch</code><dd>Specify whether to enable or disable multiarch support.  The default is
447to check for glibc start files in a multiarch location, and enable it
448if the files are found.  The auto detection is enabled for native builds,
449and for cross builds configured with <samp><span class="option">--with-sysroot</span></samp>, and without
450<samp><span class="option">--with-native-system-header-dir</span></samp>. 
451More documentation about multiarch can be found at
452<a href="https://wiki.debian.org/Multiarch">https://wiki.debian.org/Multiarch</a>.
453
454     <br><dt><code>--enable-sjlj-exceptions</code><dd>Force use of the <code>setjmp</code>/<code>longjmp</code>-based scheme for exceptions. 
455&lsquo;<samp><span class="samp">configure</span></samp>&rsquo; ordinarily picks the correct value based on the platform. 
456Only use this option if you are sure you need a different setting.
457
458     <br><dt><code>--enable-vtable-verify</code><dd>Specify whether to enable or disable the vtable verification feature. 
459Enabling this feature causes libstdc++ to be built with its virtual calls
460in verifiable mode.  This means that, when linked with libvtv, every
461virtual call in libstdc++ will verify the vtable pointer through which the
462call will be made before actually making the call.  If not linked with libvtv,
463the verifier will call stub functions (in libstdc++ itself) and do nothing. 
464If vtable verification is disabled, then libstdc++ is not built with its
465virtual calls in verifiable mode at all.  However the libvtv library will
466still be built (see <samp><span class="option">--disable-libvtv</span></samp> to turn off building libvtv). 
467<samp><span class="option">--disable-vtable-verify</span></samp> is the default.
468
469     <br><dt><code>--disable-multilib</code><dd>Specify that multiple target
470libraries to support different target variants, calling
471conventions, etc. should not be built.  The default is to build a
472predefined set of them.
473
474     <p>Some targets provide finer-grained control over which multilibs are built
475(e.g., <samp><span class="option">--disable-softfloat</span></samp>):
476          <dl>
477<dt><code>arm-*-*</code><dd>fpu, 26bit, underscore, interwork, biendian, nofmult.
478
479          <br><dt><code>m68*-*-*</code><dd>softfloat, m68881, m68000, m68020.
480
481          <br><dt><code>mips*-*-*</code><dd>single-float, biendian, softfloat.
482
483          <br><dt><code>powerpc*-*-*, rs6000*-*-*</code><dd>aix64, pthread, softfloat, powercpu, powerpccpu, powerpcos, biendian,
484sysv, aix.
485
486     </dl>
487
488     <br><dt><code>--with-multilib-list=</code><var>list</var><dt><code>--without-multilib-list</code><dd>Specify what multilibs to build. 
489Currently only implemented for arm*-*-*, sh*-*-* and x86-64-*-linux*.
490
491          <dl>
492<dt><code>arm*-*-*</code><dd><var>list</var> is either <code>default</code> or <code>aprofile</code>.  Specifying
493<code>default</code> is equivalent to omitting this option while specifying
494<code>aprofile</code> builds multilibs for each combination of ISA (<code>-marm</code> or
495<code>-mthumb</code>), architecture (<code>-march=armv7-a</code>, <code>-march=armv7ve</code>,
496or <code>-march=armv8-a</code>), FPU available (none, <code>-mfpu=vfpv3-d16</code>,
497<code>-mfpu=neon</code>, <code>-mfpu=vfpv4-d16</code>, <code>-mfpu=neon-vfpv4</code> or
498<code>-mfpu=neon-fp-armv8</code> depending on architecture) and floating-point ABI
499(<code>-mfloat-abi=softfp</code> or <code>-mfloat-abi=hard</code>).
500
501          <br><dt><code>sh*-*-*</code><dd><var>list</var> is a comma separated list of CPU names.  These must be of the
502form <code>sh*</code> or <code>m*</code> (in which case they match the compiler option
503for that processor).  The list should not contain any endian options -
504these are handled by <samp><span class="option">--with-endian</span></samp>.
505
506          <p>If <var>list</var> is empty, then there will be no multilibs for extra
507processors.  The multilib for the secondary endian remains enabled.
508
509          <p>As a special case, if an entry in the list starts with a <code>!</code>
510(exclamation point), then it is added to the list of excluded multilibs. 
511Entries of this sort should be compatible with &lsquo;<samp><span class="samp">MULTILIB_EXCLUDES</span></samp>&rsquo;
512(once the leading <code>!</code> has been stripped).
513
514          <p>If <samp><span class="option">--with-multilib-list</span></samp> is not given, then a default set of
515multilibs is selected based on the value of <samp><span class="option">--target</span></samp>.  This is
516usually the complete set of libraries, but some targets imply a more
517specialized subset.
518
519          <p>Example 1: to configure a compiler for SH4A only, but supporting both
520endians, with little endian being the default:
521          <pre class="smallexample">               --with-cpu=sh4a --with-endian=little,big --with-multilib-list=
522</pre>
523          <p>Example 2: to configure a compiler for both SH4A and SH4AL-DSP, but with
524only little endian SH4AL:
525          <pre class="smallexample">               --with-cpu=sh4a --with-endian=little,big \
526               --with-multilib-list=sh4al,!mb/m4al
527</pre>
528          <br><dt><code>x86-64-*-linux*</code><dd><var>list</var> is a comma separated list of <code>m32</code>, <code>m64</code> and
529<code>mx32</code> to enable 32-bit, 64-bit and x32 run-time libraries,
530respectively.  If <var>list</var> is empty, then there will be no multilibs
531and only the default run-time library will be enabled.
532
533          <p>If <samp><span class="option">--with-multilib-list</span></samp> is not given, then only 32-bit and
53464-bit run-time libraries will be enabled. 
535</dl>
536
537     <br><dt><code>--with-endian=</code><var>endians</var><dd>Specify what endians to use. 
538Currently only implemented for sh*-*-*.
539
540     <p><var>endians</var> may be one of the following:
541          <dl>
542<dt><code>big</code><dd>Use big endian exclusively. 
543<br><dt><code>little</code><dd>Use little endian exclusively. 
544<br><dt><code>big,little</code><dd>Use big endian by default.  Provide a multilib for little endian. 
545<br><dt><code>little,big</code><dd>Use little endian by default.  Provide a multilib for big endian. 
546</dl>
547
548     <br><dt><code>--enable-threads</code><dd>Specify that the target
549supports threads.  This affects the Objective-C compiler and runtime
550library, and exception handling for other languages like C++ and Java. 
551On some systems, this is the default.
552
553     <p>In general, the best (and, in many cases, the only known) threading
554model available will be configured for use.  Beware that on some
555systems, GCC has not been taught what threading models are generally
556available for the system.  In this case, <samp><span class="option">--enable-threads</span></samp> is an
557alias for <samp><span class="option">--enable-threads=single</span></samp>.
558
559     <br><dt><code>--disable-threads</code><dd>Specify that threading support should be disabled for the system. 
560This is an alias for <samp><span class="option">--enable-threads=single</span></samp>.
561
562     <br><dt><code>--enable-threads=</code><var>lib</var><dd>Specify that
563<var>lib</var> is the thread support library.  This affects the Objective-C
564compiler and runtime library, and exception handling for other languages
565like C++ and Java.  The possibilities for <var>lib</var> are:
566
567          <dl>
568<dt><code>aix</code><dd>AIX thread support. 
569<br><dt><code>dce</code><dd>DCE thread support. 
570<br><dt><code>lynx</code><dd>LynxOS thread support. 
571<br><dt><code>mipssde</code><dd>MIPS SDE thread support. 
572<br><dt><code>no</code><dd>This is an alias for &lsquo;<samp><span class="samp">single</span></samp>&rsquo;. 
573<br><dt><code>posix</code><dd>Generic POSIX/Unix98 thread support. 
574<br><dt><code>rtems</code><dd>RTEMS thread support. 
575<br><dt><code>single</code><dd>Disable thread support, should work for all platforms. 
576<br><dt><code>tpf</code><dd>TPF thread support. 
577<br><dt><code>vxworks</code><dd>VxWorks thread support. 
578<br><dt><code>win32</code><dd>Microsoft Win32 API thread support. 
579</dl>
580
581     <br><dt><code>--enable-tls</code><dd>Specify that the target supports TLS (Thread Local Storage).  Usually
582configure can correctly determine if TLS is supported.  In cases where
583it guesses incorrectly, TLS can be explicitly enabled or disabled with
584<samp><span class="option">--enable-tls</span></samp> or <samp><span class="option">--disable-tls</span></samp>.  This can happen if
585the assembler supports TLS but the C library does not, or if the
586assumptions made by the configure test are incorrect.
587
588     <br><dt><code>--disable-tls</code><dd>Specify that the target does not support TLS. 
589This is an alias for <samp><span class="option">--enable-tls=no</span></samp>.
590
591     <br><dt><code>--with-cpu=</code><var>cpu</var><dt><code>--with-cpu-32=</code><var>cpu</var><dt><code>--with-cpu-64=</code><var>cpu</var><dd>Specify which cpu variant the compiler should generate code for by default. 
592<var>cpu</var> will be used as the default value of the <samp><span class="option">-mcpu=</span></samp> switch. 
593This option is only supported on some targets, including ARC, ARM, i386, M68k,
594PowerPC, and SPARC.  It is mandatory for ARC.  The <samp><span class="option">--with-cpu-32</span></samp> and
595<samp><span class="option">--with-cpu-64</span></samp> options specify separate default CPUs for
59632-bit and 64-bit modes; these options are only supported for i386,
597x86-64, PowerPC, and SPARC.
598
599     <br><dt><code>--with-schedule=</code><var>cpu</var><dt><code>--with-arch=</code><var>cpu</var><dt><code>--with-arch-32=</code><var>cpu</var><dt><code>--with-arch-64=</code><var>cpu</var><dt><code>--with-tune=</code><var>cpu</var><dt><code>--with-tune-32=</code><var>cpu</var><dt><code>--with-tune-64=</code><var>cpu</var><dt><code>--with-abi=</code><var>abi</var><dt><code>--with-fpu=</code><var>type</var><dt><code>--with-float=</code><var>type</var><dd>These configure options provide default values for the <samp><span class="option">-mschedule=</span></samp>,
600<samp><span class="option">-march=</span></samp>, <samp><span class="option">-mtune=</span></samp>, <samp><span class="option">-mabi=</span></samp>, and <samp><span class="option">-mfpu=</span></samp>
601options and for <samp><span class="option">-mhard-float</span></samp> or <samp><span class="option">-msoft-float</span></samp>.  As with
602<samp><span class="option">--with-cpu</span></samp>, which switches will be accepted and acceptable values
603of the arguments depend on the target.
604
605     <br><dt><code>--with-mode=</code><var>mode</var><dd>Specify if the compiler should default to <samp><span class="option">-marm</span></samp> or <samp><span class="option">-mthumb</span></samp>. 
606This option is only supported on ARM targets.
607
608     <br><dt><code>--with-stack-offset=</code><var>num</var><dd>This option sets the default for the -mstack-offset=<var>num</var> option,
609and will thus generally also control the setting of this option for
610libraries.  This option is only supported on Epiphany targets.
611
612     <br><dt><code>--with-fpmath=</code><var>isa</var><dd>This options sets <samp><span class="option">-mfpmath=sse</span></samp> by default and specifies the default
613ISA for floating-point arithmetics.  You can select either &lsquo;<samp><span class="samp">sse</span></samp>&rsquo; which
614enables <samp><span class="option">-msse2</span></samp> or &lsquo;<samp><span class="samp">avx</span></samp>&rsquo; which enables <samp><span class="option">-mavx</span></samp> by default. 
615This option is only supported on i386 and x86-64 targets.
616
617     <br><dt><code>--with-fp-32=</code><var>mode</var><dd>On MIPS targets, set the default value for the <samp><span class="option">-mfp</span></samp> option when using
618the o32 ABI.  The possibilities for <var>mode</var> are:
619          <dl>
620<dt><code>32</code><dd>Use the o32 FP32 ABI extension, as with the <samp><span class="option">-mfp32</span></samp> command-line
621option. 
622<br><dt><code>xx</code><dd>Use the o32 FPXX ABI extension, as with the <samp><span class="option">-mfpxx</span></samp> command-line
623option. 
624<br><dt><code>64</code><dd>Use the o32 FP64 ABI extension, as with the <samp><span class="option">-mfp64</span></samp> command-line
625option. 
626</dl>
627     In the absence of this configuration option the default is to use the o32
628FP32 ABI extension.
629
630     <br><dt><code>--with-odd-spreg-32</code><dd>On MIPS targets, set the <samp><span class="option">-modd-spreg</span></samp> option by default when using
631the o32 ABI.
632
633     <br><dt><code>--without-odd-spreg-32</code><dd>On MIPS targets, set the <samp><span class="option">-mno-odd-spreg</span></samp> option by default when using
634the o32 ABI.  This is normally used in conjunction with
635<samp><span class="option">--with-fp-32=64</span></samp> in order to target the o32 FP64A ABI extension.
636
637     <br><dt><code>--with-nan=</code><var>encoding</var><dd>On MIPS targets, set the default encoding convention to use for the
638special not-a-number (NaN) IEEE 754 floating-point data.  The
639possibilities for <var>encoding</var> are:
640          <dl>
641<dt><code>legacy</code><dd>Use the legacy encoding, as with the <samp><span class="option">-mnan=legacy</span></samp> command-line
642option. 
643<br><dt><code>2008</code><dd>Use the 754-2008 encoding, as with the <samp><span class="option">-mnan=2008</span></samp> command-line
644option. 
645</dl>
646     To use this configuration option you must have an assembler version
647installed that supports the <samp><span class="option">-mnan=</span></samp> command-line option too. 
648In the absence of this configuration option the default convention is
649the legacy encoding, as when neither of the <samp><span class="option">-mnan=2008</span></samp> and
650<samp><span class="option">-mnan=legacy</span></samp> command-line options has been used.
651
652     <br><dt><code>--with-divide=</code><var>type</var><dd>Specify how the compiler should generate code for checking for
653division by zero.  This option is only supported on the MIPS target. 
654The possibilities for <var>type</var> are:
655          <dl>
656<dt><code>traps</code><dd>Division by zero checks use conditional traps (this is the default on
657systems that support conditional traps). 
658<br><dt><code>breaks</code><dd>Division by zero checks use the break instruction. 
659</dl>
660
661     <!-- If you make -with-llsc the default for additional targets, -->
662     <!-- update the -with-llsc description in the MIPS section below. -->
663     <br><dt><code>--with-llsc</code><dd>On MIPS targets, make <samp><span class="option">-mllsc</span></samp> the default when no
664<samp><span class="option">-mno-llsc</span></samp> option is passed.  This is the default for
665Linux-based targets, as the kernel will emulate them if the ISA does
666not provide them.
667
668     <br><dt><code>--without-llsc</code><dd>On MIPS targets, make <samp><span class="option">-mno-llsc</span></samp> the default when no
669<samp><span class="option">-mllsc</span></samp> option is passed.
670
671     <br><dt><code>--with-synci</code><dd>On MIPS targets, make <samp><span class="option">-msynci</span></samp> the default when no
672<samp><span class="option">-mno-synci</span></samp> option is passed.
673
674     <br><dt><code>--without-synci</code><dd>On MIPS targets, make <samp><span class="option">-mno-synci</span></samp> the default when no
675<samp><span class="option">-msynci</span></samp> option is passed.  This is the default.
676
677     <br><dt><code>--with-mips-plt</code><dd>On MIPS targets, make use of copy relocations and PLTs. 
678These features are extensions to the traditional
679SVR4-based MIPS ABIs and require support from GNU binutils
680and the runtime C library.
681
682     <br><dt><code>--enable-__cxa_atexit</code><dd>Define if you want to use __cxa_atexit, rather than atexit, to
683register C++ destructors for local statics and global objects. 
684This is essential for fully standards-compliant handling of
685destructors, but requires __cxa_atexit in libc.  This option is currently
686only available on systems with GNU libc.  When enabled, this will cause
687<samp><span class="option">-fuse-cxa-atexit</span></samp> to be passed by default.
688
689     <br><dt><code>--enable-gnu-indirect-function</code><dd>Define if you want to enable the <code>ifunc</code> attribute.  This option is
690currently only available on systems with GNU libc on certain targets.
691
692     <br><dt><code>--enable-target-optspace</code><dd>Specify that target
693libraries should be optimized for code space instead of code speed. 
694This is the default for the m32r platform.
695
696     <br><dt><code>--with-cpp-install-dir=</code><var>dirname</var><dd>Specify that the user visible <samp><span class="command">cpp</span></samp> program should be installed
697in <samp><var>prefix</var><span class="file">/</span><var>dirname</var><span class="file">/cpp</span></samp>, in addition to <var>bindir</var>.
698
699     <br><dt><code>--enable-comdat</code><dd>Enable COMDAT group support.  This is primarily used to override the
700automatically detected value.
701
702     <br><dt><code>--enable-initfini-array</code><dd>Force the use of sections <code>.init_array</code> and <code>.fini_array</code>
703(instead of <code>.init</code> and <code>.fini</code>) for constructors and
704destructors.  Option <samp><span class="option">--disable-initfini-array</span></samp> has the
705opposite effect.  If neither option is specified, the configure script
706will try to guess whether the <code>.init_array</code> and
707<code>.fini_array</code> sections are supported and, if they are, use them.
708
709     <br><dt><code>--enable-link-mutex</code><dd>When building GCC, use a mutex to avoid linking the compilers for
710multiple languages at the same time, to avoid thrashing on build
711systems with limited free memory.  The default is not to use such a mutex.
712
713     <br><dt><code>--enable-maintainer-mode</code><dd>The build rules that regenerate the Autoconf and Automake output files as
714well as the GCC master message catalog <samp><span class="file">gcc.pot</span></samp> are normally
715disabled.  This is because it can only be rebuilt if the complete source
716tree is present.  If you have changed the sources and want to rebuild the
717catalog, configuring with <samp><span class="option">--enable-maintainer-mode</span></samp> will enable
718this.  Note that you need a recent version of the <code>gettext</code> tools
719to do so.
720
721     <br><dt><code>--disable-bootstrap</code><dd>For a native build, the default configuration is to perform
722a 3-stage bootstrap of the compiler when &lsquo;<samp><span class="samp">make</span></samp>&rsquo; is invoked,
723testing that GCC can compile itself correctly.  If you want to disable
724this process, you can configure with <samp><span class="option">--disable-bootstrap</span></samp>.
725
726     <br><dt><code>--enable-bootstrap</code><dd>In special cases, you may want to perform a 3-stage build
727even if the target and host triplets are different. 
728This is possible when the host can run code compiled for
729the target (e.g. host is i686-linux, target is i486-linux). 
730Starting from GCC 4.2, to do this you have to configure explicitly
731with <samp><span class="option">--enable-bootstrap</span></samp>.
732
733     <br><dt><code>--enable-generated-files-in-srcdir</code><dd>Neither the .c and .h files that are generated from Bison and flex nor the
734info manuals and man pages that are built from the .texi files are present
735in the SVN development tree.  When building GCC from that development tree,
736or from one of our snapshots, those generated files are placed in your
737build directory, which allows for the source to be in a readonly
738directory.
739
740     <p>If you configure with <samp><span class="option">--enable-generated-files-in-srcdir</span></samp> then those
741generated files will go into the source directory.  This is mainly intended
742for generating release or prerelease tarballs of the GCC sources, since it
743is not a requirement that the users of source releases to have flex, Bison,
744or makeinfo.
745
746     <br><dt><code>--enable-version-specific-runtime-libs</code><dd>Specify
747that runtime libraries should be installed in the compiler specific
748subdirectory (<samp><var>libdir</var><span class="file">/gcc</span></samp>) rather than the usual places.  In
749addition, &lsquo;<samp><span class="samp">libstdc++</span></samp>&rsquo;'s include files will be installed into
750<samp><var>libdir</var></samp> unless you overruled it by using
751<samp><span class="option">--with-gxx-include-dir=</span><var>dirname</var></samp>.  Using this option is
752particularly useful if you intend to use several versions of GCC in
753parallel.  This is currently supported by &lsquo;<samp><span class="samp">libgfortran</span></samp>&rsquo;,
754&lsquo;<samp><span class="samp">libjava</span></samp>&rsquo;, &lsquo;<samp><span class="samp">libstdc++</span></samp>&rsquo;, and &lsquo;<samp><span class="samp">libobjc</span></samp>&rsquo;.
755
756     <br><dt><code><a name="WithAixSoname"></a>--with-aix-soname=&lsquo;</code><samp><span class="samp">aix</span></samp><code>&rsquo;, &lsquo;</code><samp><span class="samp">svr4</span></samp><code>&rsquo; or &lsquo;</code><samp><span class="samp">both</span></samp><code>&rsquo;</code><dd>Traditional AIX shared library versioning (versioned <code>Shared Object</code>
757files as members of unversioned <code>Archive Library</code> files named
758&lsquo;<samp><span class="samp">lib.a</span></samp>&rsquo;) causes numerous headaches for package managers. However,
759<code>Import Files</code> as members of <code>Archive Library</code> files allow for
760<strong>filename-based versioning</strong> of shared libraries as seen on Linux/SVR4,
761where this is called the "SONAME". But as they prevent static linking,
762<code>Import Files</code> may be used with <code>Runtime Linking</code> only, where the
763linker does search for &lsquo;<samp><span class="samp">libNAME.so</span></samp>&rsquo; before &lsquo;<samp><span class="samp">libNAME.a</span></samp>&rsquo; library
764filenames with the &lsquo;<samp><span class="samp">-lNAME</span></samp>&rsquo; linker flag.
765
766     <p><a name="AixLdCommand"></a>For detailed information please refer to the AIX
767<a href="http://www-01.ibm.com/support/knowledgecenter/search/%22the%20ld%20command%2C%20also%20called%20the%20linkage%20editor%20or%20binder%22">ld Command</a> reference.
768
769     <p>As long as shared library creation is enabled, upon:
770          <dl>
771<dt><code>--with-aix-soname=aix</code><br><dt><code>--with-aix-soname=both</code><dd> A (traditional AIX) <code>Shared Archive Library</code> file is created:
772               <ul>
773  <li>using the &lsquo;<samp><span class="samp">libNAME.a</span></samp>&rsquo; filename scheme
774  <li>with the <code>Shared Object</code> file as archive member named
775  &lsquo;<samp><span class="samp">libNAME.so.V</span></samp>&rsquo; (except for &lsquo;<samp><span class="samp">libgcc_s</span></samp>&rsquo;, where the <code>Shared
776  Object</code> file is named &lsquo;<samp><span class="samp">shr.o</span></samp>&rsquo; for backwards compatibility), which
777                    <ul>
778   <li>is used for runtime loading from inside the &lsquo;<samp><span class="samp">libNAME.a</span></samp>&rsquo; file
779   <li>is used for dynamic loading via
780   <code>dlopen("libNAME.a(libNAME.so.V)", RTLD_MEMBER)</code>
781   <li>is used for shared linking
782   <li>is used for static linking, so no separate <code>Static Archive
783   Library</code> file is needed
784  </ul>
785                </ul>
786          <br><dt><code>--with-aix-soname=both</code><br><dt><code>--with-aix-soname=svr4</code><dd> A (second) <code>Shared Archive Library</code> file is created:
787               <ul>
788 <li>using the &lsquo;<samp><span class="samp">libNAME.so.V</span></samp>&rsquo; filename scheme
789 <li>with the <code>Shared Object</code> file as archive member named
790 &lsquo;<samp><span class="samp">shr.o</span></samp>&rsquo;, which
791                    <ul>
792   <li>is created with the <code>-G linker flag</code>
793   <li>has the <code>F_LOADONLY</code> flag set
794   <li>is used for runtime loading from inside the &lsquo;<samp><span class="samp">libNAME.so.V</span></samp>&rsquo; file
795   <li>is used for dynamic loading via <code>dlopen("libNAME.so.V(shr.o)",
796   RTLD_MEMBER)</code>
797  </ul>
798                <li>with the <code>Import File</code> as archive member named &lsquo;<samp><span class="samp">shr.imp</span></samp>&rsquo;,
799 which
800                    <ul>
801   <li>refers to &lsquo;<samp><span class="samp">libNAME.so.V(shr.o)</span></samp>&rsquo; as the "SONAME", to be recorded
802   in the <code>Loader Section</code> of subsequent binaries
803   <li>indicates whether &lsquo;<samp><span class="samp">libNAME.so.V(shr.o)</span></samp>&rsquo; is 32 or 64 bit
804   <li>lists all the public symbols exported by &lsquo;<samp><span class="samp">lib.so.V(shr.o)</span></samp>&rsquo;,
805   eventually decorated with the <code>&lsquo;</code><samp><span class="samp">weak</span></samp><code>&rsquo; Keyword</code>
806   <li>is necessary for shared linking against &lsquo;<samp><span class="samp">lib.so.V(shr.o)</span></samp>&rsquo;
807   </ul>
808                 </ul>
809            A symbolic link using the &lsquo;<samp><span class="samp">libNAME.so</span></samp>&rsquo; filename scheme is created:
810               <ul>
811  <li>pointing to the &lsquo;<samp><span class="samp">libNAME.so.V</span></samp>&rsquo; <code>Shared Archive Library</code> file
812  <li>to permit the <code>ld Command</code> to find &lsquo;<samp><span class="samp">lib.so.V(shr.imp)</span></samp>&rsquo; via
813  the &lsquo;<samp><span class="samp">-lNAME</span></samp>&rsquo; argument (requires <code>Runtime Linking</code> to be enabled)
814  <li>to permit dynamic loading of &lsquo;<samp><span class="samp">lib.so.V(shr.o)</span></samp>&rsquo; without the need
815  to specify the version number via <code>dlopen("libNAME.so(shr.o)",
816  RTLD_MEMBER)</code>
817  </ul>
818          </dl>
819
820     <p>As long as static library creation is enabled, upon:
821          <dl>
822<dt><code>--with-aix-soname=svr4</code><dd> A <code>Static Archive Library</code> is created:
823               <ul>
824 <li>using the &lsquo;<samp><span class="samp">libNAME.a</span></samp>&rsquo; filename scheme
825 <li>with all the <code>Static Object</code> files as archive members, which
826                    <ul>
827   <li>are used for static linking
828  </ul>
829                </ul>
830          </dl>
831
832     <p>While the aix-soname=&lsquo;<samp><span class="samp">svr4</span></samp>&rsquo; option does not create <code>Shared Object</code>
833files as members of unversioned <code>Archive Library</code> files any more, package
834managers still are responsible to
835<a href="./specific.html#TransferAixShobj">transfer</a> <code>Shared Object</code> files
836found as member of a previously installed unversioned <code>Archive Library</code>
837file into the newly installed <code>Archive Library</code> file with the same
838filename.
839
840     <p><em>WARNING:</em> Creating <code>Shared Object</code> files with <code>Runtime Linking</code>
841enabled may bloat the TOC, eventually leading to <code>TOC overflow</code> errors,
842requiring the use of either the <samp><span class="option">-Wl,-bbigtoc</span></samp> linker flag (seen to
843break with the <code>GDB</code> debugger) or some of the TOC-related compiler flags,
844see &ldquo;RS/6000 and PowerPC Options&rdquo; in the main manual.
845
846     <p><samp><span class="option">--with-aix-soname</span></samp> is currently supported by &lsquo;<samp><span class="samp">libgcc_s</span></samp>&rsquo; only, so
847this option is still experimental and not for normal use yet.
848
849     <p>Default is the traditional behavior <samp><span class="option">--with-aix-soname=&lsquo;</span><samp><span class="samp">aix</span></samp><span class="option">&rsquo;</span></samp>.
850
851     <br><dt><code>--enable-languages=</code><var>lang1</var><code>,</code><var>lang2</var><code>,...</code><dd>Specify that only a particular subset of compilers and
852their runtime libraries should be built.  For a list of valid values for
853<var>langN</var> you can issue the following command in the
854<samp><span class="file">gcc</span></samp> directory of your GCC source tree:<br>
855     <pre class="smallexample">          grep ^language= */config-lang.in
856</pre>
857     <p>Currently, you can use any of the following:
858<code>all</code>, <code>ada</code>, <code>c</code>, <code>c++</code>, <code>fortran</code>,
859<code>go</code>, <code>java</code>, <code>jit</code>, <code>lto</code>, <code>objc</code>, <code>obj-c++</code>. 
860Building the Ada compiler has special requirements, see below. 
861If you do not pass this flag, or specify the option <code>all</code>, then all
862default languages available in the <samp><span class="file">gcc</span></samp> sub-tree will be configured. 
863Ada, Go, Jit, and Objective-C++ are not default languages.  LTO is not a
864default language, but is built by default because <samp><span class="option">--enable-lto</span></samp> is
865enabled by default.  The other languages are default languages.
866
867     <br><dt><code>--enable-stage1-languages=</code><var>lang1</var><code>,</code><var>lang2</var><code>,...</code><dd>Specify that a particular subset of compilers and their runtime
868libraries should be built with the system C compiler during stage 1 of
869the bootstrap process, rather than only in later stages with the
870bootstrapped C compiler.  The list of valid values is the same as for
871<samp><span class="option">--enable-languages</span></samp>, and the option <code>all</code> will select all
872of the languages enabled by <samp><span class="option">--enable-languages</span></samp>.  This option is
873primarily useful for GCC development; for instance, when a development
874version of the compiler cannot bootstrap due to compiler bugs, or when
875one is debugging front ends other than the C front end.  When this
876option is used, one can then build the target libraries for the
877specified languages with the stage-1 compiler by using <samp><span class="command">make
878stage1-bubble all-target</span></samp>, or run the testsuite on the stage-1 compiler
879for the specified languages using <samp><span class="command">make stage1-start check-gcc</span></samp>.
880
881     <br><dt><code>--disable-libada</code><dd>Specify that the run-time libraries and tools used by GNAT should not
882be built.  This can be useful for debugging, or for compatibility with
883previous Ada build procedures, when it was required to explicitly
884do a &lsquo;<samp><span class="samp">make -C gcc gnatlib_and_tools</span></samp>&rsquo;.
885
886     <br><dt><code>--disable-libsanitizer</code><dd>Specify that the run-time libraries for the various sanitizers should
887not be built.
888
889     <br><dt><code>--disable-libssp</code><dd>Specify that the run-time libraries for stack smashing protection
890should not be built.
891
892     <br><dt><code>--disable-libquadmath</code><dd>Specify that the GCC quad-precision math library should not be built. 
893On some systems, the library is required to be linkable when building
894the Fortran front end, unless <samp><span class="option">--disable-libquadmath-support</span></samp>
895is used.
896
897     <br><dt><code>--disable-libquadmath-support</code><dd>Specify that the Fortran front end and <code>libgfortran</code> do not add
898support for <code>libquadmath</code> on systems supporting it.
899
900     <br><dt><code>--disable-libgomp</code><dd>Specify that the GNU Offloading and Multi Processing Runtime Library
901should not be built.
902
903     <br><dt><code>--disable-libvtv</code><dd>Specify that the run-time libraries used by vtable verification
904should not be built.
905
906     <br><dt><code>--with-dwarf2</code><dd>Specify that the compiler should
907use DWARF 2 debugging information as the default.
908
909     <br><dt><code>--with-advance-toolchain=</code><var>at</var><dd>On 64-bit PowerPC Linux systems, configure the compiler to use the
910header files, library files, and the dynamic linker from the Advance
911Toolchain release <var>at</var> instead of the default versions that are
912provided by the Linux distribution.  In general, this option is
913intended for the developers of GCC, and it is not intended for general
914use.
915
916     <br><dt><code>--enable-targets=all</code><dt><code>--enable-targets=</code><var>target_list</var><dd>Some GCC targets, e.g. powerpc64-linux, build bi-arch compilers. 
917These are compilers that are able to generate either 64-bit or 32-bit
918code.  Typically, the corresponding 32-bit target, e.g. 
919powerpc-linux for powerpc64-linux, only generates 32-bit code.  This
920option enables the 32-bit target to be a bi-arch compiler, which is
921useful when you want a bi-arch compiler that defaults to 32-bit, and
922you are building a bi-arch or multi-arch binutils in a combined tree. 
923On mips-linux, this will build a tri-arch compiler (ABI o32/n32/64),
924defaulted to o32. 
925Currently, this option only affects sparc-linux, powerpc-linux, x86-linux,
926mips-linux and s390-linux.
927
928     <br><dt><code>--enable-default-pie</code><dd>Turn on <samp><span class="option">-fPIE</span></samp> and <samp><span class="option">-pie</span></samp> by default.
929
930     <br><dt><code>--enable-secureplt</code><dd>This option enables <samp><span class="option">-msecure-plt</span></samp> by default for powerpc-linux. 
931See &ldquo;RS/6000 and PowerPC Options&rdquo; in the main manual
932
933     <br><dt><code>--enable-default-ssp</code><dd>Turn on <samp><span class="option">-fstack-protector-strong</span></samp> by default.
934
935     <br><dt><code>--enable-cld</code><dd>This option enables <samp><span class="option">-mcld</span></samp> by default for 32-bit x86 targets. 
936See &ldquo;i386 and x86-64 Options&rdquo; in the main manual
937
938     <br><dt><code>--enable-win32-registry</code><dt><code>--enable-win32-registry=</code><var>key</var><dt><code>--disable-win32-registry</code><dd>The <samp><span class="option">--enable-win32-registry</span></samp> option enables Microsoft Windows-hosted GCC
939to look up installations paths in the registry using the following key:
940
941     <pre class="smallexample">          <code>HKEY_LOCAL_MACHINE\SOFTWARE\Free Software Foundation\</code><var>key</var>
942</pre>
943     <p><var>key</var> defaults to GCC version number, and can be overridden by the
944<samp><span class="option">--enable-win32-registry=</span><var>key</var></samp> option.  Vendors and distributors
945who use custom installers are encouraged to provide a different key,
946perhaps one comprised of vendor name and GCC version number, to
947avoid conflict with existing installations.  This feature is enabled
948by default, and can be disabled by <samp><span class="option">--disable-win32-registry</span></samp>
949option.  This option has no effect on the other hosts.
950
951     <br><dt><code>--nfp</code><dd>Specify that the machine does not have a floating point unit.  This
952option only applies to &lsquo;<samp><span class="samp">m68k-sun-sunos</span><var>n</var></samp>&rsquo;.  On any other
953system, <samp><span class="option">--nfp</span></samp> has no effect.
954
955     <br><dt><code>--enable-werror</code><dt><code>--disable-werror</code><dt><code>--enable-werror=yes</code><dt><code>--enable-werror=no</code><dd>When you specify this option, it controls whether certain files in the
956compiler are built with <samp><span class="option">-Werror</span></samp> in bootstrap stage2 and later. 
957If you don't specify it, <samp><span class="option">-Werror</span></samp> is turned on for the main
958development trunk.  However it defaults to off for release branches and
959final releases.  The specific files which get <samp><span class="option">-Werror</span></samp> are
960controlled by the Makefiles.
961
962     <br><dt><code>--enable-checking</code><dt><code>--enable-checking=</code><var>list</var><dd>When you specify this option, the compiler is built to perform internal
963consistency checks of the requested complexity.  This does not change the
964generated code, but adds error checking within the compiler.  This will
965slow down the compiler and may only work properly if you are building
966the compiler with GCC.  This is &lsquo;<samp><span class="samp">yes</span></samp>&rsquo; by default when building
967from SVN or snapshots, but &lsquo;<samp><span class="samp">release</span></samp>&rsquo; for releases.  The default
968for building the stage1 compiler is &lsquo;<samp><span class="samp">yes</span></samp>&rsquo;.  More control
969over the checks may be had by specifying <var>list</var>.  The categories of
970checks available are &lsquo;<samp><span class="samp">yes</span></samp>&rsquo; (most common checks
971&lsquo;<samp><span class="samp">assert,misc,tree,gc,rtlflag,runtime</span></samp>&rsquo;), &lsquo;<samp><span class="samp">no</span></samp>&rsquo; (no checks at
972all), &lsquo;<samp><span class="samp">all</span></samp>&rsquo; (all but &lsquo;<samp><span class="samp">valgrind</span></samp>&rsquo;), &lsquo;<samp><span class="samp">release</span></samp>&rsquo; (cheapest
973checks &lsquo;<samp><span class="samp">assert,runtime</span></samp>&rsquo;) or &lsquo;<samp><span class="samp">none</span></samp>&rsquo; (same as &lsquo;<samp><span class="samp">no</span></samp>&rsquo;). 
974Individual checks can be enabled with these flags &lsquo;<samp><span class="samp">assert</span></samp>&rsquo;,
975&lsquo;<samp><span class="samp">df</span></samp>&rsquo;, &lsquo;<samp><span class="samp">fold</span></samp>&rsquo;, &lsquo;<samp><span class="samp">gc</span></samp>&rsquo;, &lsquo;<samp><span class="samp">gcac</span></samp>&rsquo; &lsquo;<samp><span class="samp">misc</span></samp>&rsquo;, &lsquo;<samp><span class="samp">rtl</span></samp>&rsquo;,
976&lsquo;<samp><span class="samp">rtlflag</span></samp>&rsquo;, &lsquo;<samp><span class="samp">runtime</span></samp>&rsquo;, &lsquo;<samp><span class="samp">tree</span></samp>&rsquo;, and &lsquo;<samp><span class="samp">valgrind</span></samp>&rsquo;.
977
978     <p>The &lsquo;<samp><span class="samp">valgrind</span></samp>&rsquo; check requires the external <samp><span class="command">valgrind</span></samp>
979simulator, available from <a href="http://valgrind.org/">http://valgrind.org/</a>.  The
980&lsquo;<samp><span class="samp">df</span></samp>&rsquo;, &lsquo;<samp><span class="samp">rtl</span></samp>&rsquo;, &lsquo;<samp><span class="samp">gcac</span></samp>&rsquo; and &lsquo;<samp><span class="samp">valgrind</span></samp>&rsquo; checks are very expensive. 
981To disable all checking, &lsquo;<samp><span class="samp">--disable-checking</span></samp>&rsquo; or
982&lsquo;<samp><span class="samp">--enable-checking=none</span></samp>&rsquo; must be explicitly requested.  Disabling
983assertions will make the compiler and runtime slightly faster but
984increase the risk of undetected internal errors causing wrong code to be
985generated.
986
987     <br><dt><code>--disable-stage1-checking</code><dt><code>--enable-stage1-checking</code><dt><code>--enable-stage1-checking=</code><var>list</var><dd>If no <samp><span class="option">--enable-checking</span></samp> option is specified the stage1
988compiler will be built with &lsquo;<samp><span class="samp">yes</span></samp>&rsquo; checking enabled, otherwise
989the stage1 checking flags are the same as specified by
990<samp><span class="option">--enable-checking</span></samp>.  To build the stage1 compiler with
991different checking options use <samp><span class="option">--enable-stage1-checking</span></samp>. 
992The list of checking options is the same as for <samp><span class="option">--enable-checking</span></samp>. 
993If your system is too slow or too small to bootstrap a released compiler
994with checking for stage1 enabled, you can use &lsquo;<samp><span class="samp">--disable-stage1-checking</span></samp>&rsquo;
995to disable checking for the stage1 compiler.
996
997     <br><dt><code>--enable-coverage</code><dt><code>--enable-coverage=</code><var>level</var><dd>With this option, the compiler is built to collect self coverage
998information, every time it is run.  This is for internal development
999purposes, and only works when the compiler is being built with gcc.  The
1000<var>level</var> argument controls whether the compiler is built optimized or
1001not, values are &lsquo;<samp><span class="samp">opt</span></samp>&rsquo; and &lsquo;<samp><span class="samp">noopt</span></samp>&rsquo;.  For coverage analysis you
1002want to disable optimization, for performance analysis you want to
1003enable optimization.  When coverage is enabled, the default level is
1004without optimization.
1005
1006     <br><dt><code>--enable-gather-detailed-mem-stats</code><dd>When this option is specified more detailed information on memory
1007allocation is gathered.  This information is printed when using
1008<samp><span class="option">-fmem-report</span></samp>.
1009
1010     <br><dt><code>--enable-valgrind-annotations</code><dd>Mark selected memory related operations in the compiler when run under
1011valgrind to suppress false positives.
1012
1013     <br><dt><code>--enable-nls</code><dt><code>--disable-nls</code><dd>The <samp><span class="option">--enable-nls</span></samp> option enables Native Language Support (NLS),
1014which lets GCC output diagnostics in languages other than American
1015English.  Native Language Support is enabled by default if not doing a
1016canadian cross build.  The <samp><span class="option">--disable-nls</span></samp> option disables NLS.
1017
1018     <br><dt><code>--with-included-gettext</code><dd>If NLS is enabled, the <samp><span class="option">--with-included-gettext</span></samp> option causes the build
1019procedure to prefer its copy of GNU <samp><span class="command">gettext</span></samp>.
1020
1021     <br><dt><code>--with-catgets</code><dd>If NLS is enabled, and if the host lacks <code>gettext</code> but has the
1022inferior <code>catgets</code> interface, the GCC build procedure normally
1023ignores <code>catgets</code> and instead uses GCC's copy of the GNU
1024<code>gettext</code> library.  The <samp><span class="option">--with-catgets</span></samp> option causes the
1025build procedure to use the host's <code>catgets</code> in this situation.
1026
1027     <br><dt><code>--with-libiconv-prefix=</code><var>dir</var><dd>Search for libiconv header files in <samp><var>dir</var><span class="file">/include</span></samp> and
1028libiconv library files in <samp><var>dir</var><span class="file">/lib</span></samp>.
1029
1030     <br><dt><code>--enable-obsolete</code><dd>Enable configuration for an obsoleted system.  If you attempt to
1031configure GCC for a system (build, host, or target) which has been
1032obsoleted, and you do not specify this flag, configure will halt with an
1033error message.
1034
1035     <p>All support for systems which have been obsoleted in one release of GCC
1036is removed entirely in the next major release, unless someone steps
1037forward to maintain the port.
1038
1039     <br><dt><code>--enable-decimal-float</code><dt><code>--enable-decimal-float=yes</code><dt><code>--enable-decimal-float=no</code><dt><code>--enable-decimal-float=bid</code><dt><code>--enable-decimal-float=dpd</code><dt><code>--disable-decimal-float</code><dd>Enable (or disable) support for the C decimal floating point extension
1040that is in the IEEE 754-2008 standard.  This is enabled by default only
1041on PowerPC, i386, and x86_64 GNU/Linux systems.  Other systems may also
1042support it, but require the user to specifically enable it.  You can
1043optionally control which decimal floating point format is used (either
1044&lsquo;<samp><span class="samp">bid</span></samp>&rsquo; or &lsquo;<samp><span class="samp">dpd</span></samp>&rsquo;).  The &lsquo;<samp><span class="samp">bid</span></samp>&rsquo; (binary integer decimal)
1045format is default on i386 and x86_64 systems, and the &lsquo;<samp><span class="samp">dpd</span></samp>&rsquo;
1046(densely packed decimal) format is default on PowerPC systems.
1047
1048     <br><dt><code>--enable-fixed-point</code><dt><code>--disable-fixed-point</code><dd>Enable (or disable) support for C fixed-point arithmetic. 
1049This option is enabled by default for some targets (such as MIPS) which
1050have hardware-support for fixed-point operations.  On other targets, you
1051may enable this option manually.
1052
1053     <br><dt><code>--with-long-double-128</code><dd>Specify if <code>long double</code> type should be 128-bit by default on selected
1054GNU/Linux architectures.  If using <code>--without-long-double-128</code>,
1055<code>long double</code> will be by default 64-bit, the same as <code>double</code> type. 
1056When neither of these configure options are used, the default will be
1057128-bit <code>long double</code> when built against GNU C Library 2.4 and later,
105864-bit <code>long double</code> otherwise.
1059
1060     <br><dt><code>--enable-fdpic</code><dd>On SH Linux systems, generate ELF FDPIC code.
1061
1062     <br><dt><code>--with-gmp=</code><var>pathname</var><dt><code>--with-gmp-include=</code><var>pathname</var><dt><code>--with-gmp-lib=</code><var>pathname</var><dt><code>--with-mpfr=</code><var>pathname</var><dt><code>--with-mpfr-include=</code><var>pathname</var><dt><code>--with-mpfr-lib=</code><var>pathname</var><dt><code>--with-mpc=</code><var>pathname</var><dt><code>--with-mpc-include=</code><var>pathname</var><dt><code>--with-mpc-lib=</code><var>pathname</var><dd>If you want to build GCC but do not have the GMP library, the MPFR
1063library and/or the MPC library installed in a standard location and
1064do not have their sources present in the GCC source tree then you
1065can explicitly specify the directory where they are installed
1066(&lsquo;<samp><span class="samp">--with-gmp=</span><var>gmpinstalldir</var></samp>&rsquo;,
1067&lsquo;<samp><span class="samp">--with-mpfr=</span><var>mpfrinstalldir</var></samp>&rsquo;,
1068&lsquo;<samp><span class="samp">--with-mpc=</span><var>mpcinstalldir</var></samp>&rsquo;).  The
1069<samp><span class="option">--with-gmp=</span><var>gmpinstalldir</var></samp> option is shorthand for
1070<samp><span class="option">--with-gmp-lib=</span><var>gmpinstalldir</var><span class="option">/lib</span></samp> and
1071<samp><span class="option">--with-gmp-include=</span><var>gmpinstalldir</var><span class="option">/include</span></samp>.  Likewise the
1072<samp><span class="option">--with-mpfr=</span><var>mpfrinstalldir</var></samp> option is shorthand for
1073<samp><span class="option">--with-mpfr-lib=</span><var>mpfrinstalldir</var><span class="option">/lib</span></samp> and
1074<samp><span class="option">--with-mpfr-include=</span><var>mpfrinstalldir</var><span class="option">/include</span></samp>, also the
1075<samp><span class="option">--with-mpc=</span><var>mpcinstalldir</var></samp> option is shorthand for
1076<samp><span class="option">--with-mpc-lib=</span><var>mpcinstalldir</var><span class="option">/lib</span></samp> and
1077<samp><span class="option">--with-mpc-include=</span><var>mpcinstalldir</var><span class="option">/include</span></samp>.  If these
1078shorthand assumptions are not correct, you can use the explicit
1079include and lib options directly.  You might also need to ensure the
1080shared libraries can be found by the dynamic linker when building and
1081using GCC, for example by setting the runtime shared library path
1082variable (<samp><span class="env">LD_LIBRARY_PATH</span></samp> on GNU/Linux and Solaris systems).
1083
1084     <p>These flags are applicable to the host platform only.  When building
1085a cross compiler, they will not be used to configure target libraries.
1086
1087     <br><dt><code>--with-isl=</code><var>pathname</var><dt><code>--with-isl-include=</code><var>pathname</var><dt><code>--with-isl-lib=</code><var>pathname</var><dd>If you do not have the isl library installed in a standard location and you
1088want to build GCC, you can explicitly specify the directory where it is
1089installed (&lsquo;<samp><span class="samp">--with-isl=</span><var>islinstalldir</var></samp>&rsquo;). The
1090<samp><span class="option">--with-isl=</span><var>islinstalldir</var></samp> option is shorthand for
1091<samp><span class="option">--with-isl-lib=</span><var>islinstalldir</var><span class="option">/lib</span></samp> and
1092<samp><span class="option">--with-isl-include=</span><var>islinstalldir</var><span class="option">/include</span></samp>. If this
1093shorthand assumption is not correct, you can use the explicit
1094include and lib options directly.
1095
1096     <p>These flags are applicable to the host platform only.  When building
1097a cross compiler, they will not be used to configure target libraries.
1098
1099     <br><dt><code>--with-stage1-ldflags=</code><var>flags</var><dd>This option may be used to set linker flags to be used when linking
1100stage 1 of GCC.  These are also used when linking GCC if configured with
1101<samp><span class="option">--disable-bootstrap</span></samp>.  If <samp><span class="option">--with-stage1-libs</span></samp> is not set to a
1102value, then the default is &lsquo;<samp><span class="samp">-static-libstdc++ -static-libgcc</span></samp>&rsquo;, if
1103supported.
1104
1105     <br><dt><code>--with-stage1-libs=</code><var>libs</var><dd>This option may be used to set libraries to be used when linking stage 1
1106of GCC.  These are also used when linking GCC if configured with
1107<samp><span class="option">--disable-bootstrap</span></samp>.
1108
1109     <br><dt><code>--with-boot-ldflags=</code><var>flags</var><dd>This option may be used to set linker flags to be used when linking
1110stage 2 and later when bootstrapping GCC.  If &ndash;with-boot-libs
1111is not is set to a value, then the default is
1112&lsquo;<samp><span class="samp">-static-libstdc++ -static-libgcc</span></samp>&rsquo;.
1113
1114     <br><dt><code>--with-boot-libs=</code><var>libs</var><dd>This option may be used to set libraries to be used when linking stage 2
1115and later when bootstrapping GCC.
1116
1117     <br><dt><code>--with-debug-prefix-map=</code><var>map</var><dd>Convert source directory names using <samp><span class="option">-fdebug-prefix-map</span></samp> when
1118building runtime libraries.  &lsquo;<samp><var>map</var></samp>&rsquo; is a space-separated
1119list of maps of the form &lsquo;<samp><var>old</var><span class="samp">=</span><var>new</var></samp>&rsquo;.
1120
1121     <br><dt><code>--enable-linker-build-id</code><dd>Tells GCC to pass <samp><span class="option">--build-id</span></samp> option to the linker for all final
1122links (links performed without the <samp><span class="option">-r</span></samp> or <samp><span class="option">--relocatable</span></samp>
1123option), if the linker supports it.  If you specify
1124<samp><span class="option">--enable-linker-build-id</span></samp>, but your linker does not
1125support <samp><span class="option">--build-id</span></samp> option, a warning is issued and the
1126<samp><span class="option">--enable-linker-build-id</span></samp> option is ignored.  The default is off.
1127
1128     <br><dt><code>--with-linker-hash-style=</code><var>choice</var><dd>Tells GCC to pass <samp><span class="option">--hash-style=</span><var>choice</var></samp> option to the
1129linker for all final links. <var>choice</var> can be one of
1130&lsquo;<samp><span class="samp">sysv</span></samp>&rsquo;, &lsquo;<samp><span class="samp">gnu</span></samp>&rsquo;, and &lsquo;<samp><span class="samp">both</span></samp>&rsquo; where &lsquo;<samp><span class="samp">sysv</span></samp>&rsquo; is the default.
1131
1132     <br><dt><code>--enable-gnu-unique-object</code><dt><code>--disable-gnu-unique-object</code><dd>Tells GCC to use the gnu_unique_object relocation for C++ template
1133static data members and inline function local statics.  Enabled by
1134default for a toolchain with an assembler that accepts it and
1135GLIBC 2.11 or above, otherwise disabled.
1136
1137     <br><dt><code>--with-diagnostics-color=</code><var>choice</var><dd>Tells GCC to use <var>choice</var> as the default for <samp><span class="option">-fdiagnostics-color=</span></samp>
1138option (if not used explicitly on the command line).  <var>choice</var>
1139can be one of &lsquo;<samp><span class="samp">never</span></samp>&rsquo;, &lsquo;<samp><span class="samp">auto</span></samp>&rsquo;, &lsquo;<samp><span class="samp">always</span></samp>&rsquo;, and &lsquo;<samp><span class="samp">auto-if-env</span></samp>&rsquo;
1140where &lsquo;<samp><span class="samp">auto</span></samp>&rsquo; is the default.  &lsquo;<samp><span class="samp">auto-if-env</span></samp>&rsquo; means that
1141<samp><span class="option">-fdiagnostics-color=auto</span></samp> will be the default if <code>GCC_COLORS</code>
1142is present and non-empty in the environment, and
1143<samp><span class="option">-fdiagnostics-color=never</span></samp> otherwise.
1144
1145     <br><dt><code>--enable-lto</code><dt><code>--disable-lto</code><dd>Enable support for link-time optimization (LTO).  This is enabled by
1146default, and may be disabled using <samp><span class="option">--disable-lto</span></samp>.
1147
1148     <br><dt><code>--enable-linker-plugin-configure-flags=FLAGS</code><dt><code>--enable-linker-plugin-flags=FLAGS</code><dd>By default, linker plugins (such as the LTO plugin) are built for the
1149host system architecture.  For the case that the linker has a
1150different (but run-time compatible) architecture, these flags can be
1151specified to build plugins that are compatible to the linker.  For
1152example, if you are building GCC for a 64-bit x86_64
1153(&lsquo;<samp><span class="samp">x86_64-unknown-linux-gnu</span></samp>&rsquo;) host system, but have a 32-bit x86
1154GNU/Linux (&lsquo;<samp><span class="samp">i686-pc-linux-gnu</span></samp>&rsquo;) linker executable (which is
1155executable on the former system), you can configure GCC as follows for
1156getting compatible linker plugins:
1157
1158     <pre class="smallexample">          % <var>srcdir</var>/configure \
1159              --host=x86_64-unknown-linux-gnu \
1160              --enable-linker-plugin-configure-flags=--host=i686-pc-linux-gnu \
1161              --enable-linker-plugin-flags='CC=gcc\ -m32\ -Wl,-rpath,[...]/i686-pc-linux-gnu/lib'
1162</pre>
1163     <br><dt><code>--with-plugin-ld=</code><var>pathname</var><dd>Enable an alternate linker to be used at link-time optimization (LTO)
1164link time when <samp><span class="option">-fuse-linker-plugin</span></samp> is enabled. 
1165This linker should have plugin support such as gold starting with
1166version 2.20 or GNU ld starting with version 2.21. 
1167See <samp><span class="option">-fuse-linker-plugin</span></samp> for details.
1168
1169     <br><dt><code>--enable-canonical-system-headers</code><dt><code>--disable-canonical-system-headers</code><dd>Enable system header path canonicalization for <samp><span class="file">libcpp</span></samp>.  This can
1170produce shorter header file paths in diagnostics and dependency output
1171files, but these changed header paths may conflict with some compilation
1172environments.  Enabled by default, and may be disabled using
1173<samp><span class="option">--disable-canonical-system-headers</span></samp>.
1174
1175     <br><dt><code>--with-glibc-version=</code><var>major</var><code>.</code><var>minor</var><dd>Tell GCC that when the GNU C Library (glibc) is used on the target it
1176will be version <var>major</var>.<var>minor</var> or later.  Normally this can
1177be detected from the C library's header files, but this option may be
1178needed when bootstrapping a cross toolchain without the header files
1179available for building the initial bootstrap compiler.
1180
1181     <p>If GCC is configured with some multilibs that use glibc and some that
1182do not, this option applies only to the multilibs that use glibc. 
1183However, such configurations may not work well as not all the relevant
1184configuration in GCC is on a per-multilib basis.
1185
1186     <br><dt><code>--enable-as-accelerator-for=</code><var>target</var><dd>Build as offload target compiler. Specify offload host triple by <var>target</var>.
1187
1188     <br><dt><code>--enable-offload-targets=</code><var>target1</var><code>[=</code><var>path1</var><code>],...,</code><var>targetN</var><code>[=</code><var>pathN</var><code>]</code><dd>Enable offloading to targets <var>target1</var>, <small class="dots">...</small>, <var>targetN</var>. 
1189Offload compilers are expected to be already installed.  Default search
1190path for them is <samp><var>exec-prefix</var></samp>, but it can be changed by
1191specifying paths <var>path1</var>, <small class="dots">...</small>, <var>pathN</var>.
1192
1193     <pre class="smallexample">          % <var>srcdir</var>/configure \
1194              --enable-offload-target=i686-unknown-linux-gnu=/path/to/i686/compiler,x86_64-pc-linux-gnu
1195</pre>
1196     <p>If &lsquo;<samp><span class="samp">hsa</span></samp>&rsquo; is specified as one of the targets, the compiler will be
1197built with support for HSA GPU accelerators.  Because the same
1198compiler will emit the accelerator code, no path should be specified.
1199
1200     <br><dt><code>--with-hsa-runtime=</code><var>pathname</var><dt><code>--with-hsa-runtime-include=</code><var>pathname</var><dt><code>--with-hsa-runtime-lib=</code><var>pathname</var><dd>
1201If you configure GCC with HSA offloading but do not have the HSA
1202run-time library installed in a standard location then you can
1203explicitly specify the directory where they are installed.  The
1204<samp><span class="option">--with-hsa-runtime=</span><var>hsainstalldir</var></samp> option is a
1205shorthand for
1206<samp><span class="option">--with-hsa-runtime-lib=</span><var>hsainstalldir</var><span class="option">/lib</span></samp> and
1207<samp><span class="option">--with-hsa-runtime-include=</span><var>hsainstalldir</var><span class="option">/include</span></samp>.
1208
1209     <br><dt><code>--with-hsa-kmt-lib=</code><var>pathname</var><dd>
1210If you configure GCC with HSA offloading but do not have the HSA
1211KMT library installed in a standard location then you can
1212explicitly specify the directory where it resides. 
1213</dl>
1214
1215<h4 class="subheading"><a name="TOC3"></a>Cross-Compiler-Specific Options</h4>
1216
1217<p>The following options only apply to building cross compilers.
1218
1219     <dl>
1220<dt><code>--with-sysroot</code><dt><code>--with-sysroot=</code><var>dir</var><dd>Tells GCC to consider <var>dir</var> as the root of a tree that contains
1221(a subset of) the root filesystem of the target operating system. 
1222Target system headers, libraries and run-time object files will be
1223searched for in there.  More specifically, this acts as if
1224<samp><span class="option">--sysroot=</span><var>dir</var></samp> was added to the default options of the built
1225compiler.  The specified directory is not copied into the
1226install tree, unlike the options <samp><span class="option">--with-headers</span></samp> and
1227<samp><span class="option">--with-libs</span></samp> that this option obsoletes.  The default value,
1228in case <samp><span class="option">--with-sysroot</span></samp> is not given an argument, is
1229<samp><span class="option">${gcc_tooldir}/sys-root</span></samp>.  If the specified directory is a
1230subdirectory of <samp><span class="option">${exec_prefix}</span></samp>, then it will be found relative to
1231the GCC binaries if the installation tree is moved.
1232
1233     <p>This option affects the system root for the compiler used to build
1234target libraries (which runs on the build system) and the compiler newly
1235installed with <code>make install</code>; it does not affect the compiler which is
1236used to build GCC itself.
1237
1238     <p>If you specify the <samp><span class="option">--with-native-system-header-dir=</span><var>dirname</var></samp>
1239option then the compiler will search that directory within <var>dirname</var> for
1240native system headers rather than the default <samp><span class="file">/usr/include</span></samp>.
1241
1242     <br><dt><code>--with-build-sysroot</code><dt><code>--with-build-sysroot=</code><var>dir</var><dd>Tells GCC to consider <var>dir</var> as the system root (see
1243<samp><span class="option">--with-sysroot</span></samp>) while building target libraries, instead of
1244the directory specified with <samp><span class="option">--with-sysroot</span></samp>.  This option is
1245only useful when you are already using <samp><span class="option">--with-sysroot</span></samp>.  You
1246can use <samp><span class="option">--with-build-sysroot</span></samp> when you are configuring with
1247<samp><span class="option">--prefix</span></samp> set to a directory that is different from the one in
1248which you are installing GCC and your target libraries.
1249
1250     <p>This option affects the system root for the compiler used to build
1251target libraries (which runs on the build system); it does not affect
1252the compiler which is used to build GCC itself.
1253
1254     <p>If you specify the <samp><span class="option">--with-native-system-header-dir=</span><var>dirname</var></samp>
1255option then the compiler will search that directory within <var>dirname</var> for
1256native system headers rather than the default <samp><span class="file">/usr/include</span></samp>.
1257
1258     <br><dt><code>--with-headers</code><dt><code>--with-headers=</code><var>dir</var><dd>Deprecated in favor of <samp><span class="option">--with-sysroot</span></samp>. 
1259Specifies that target headers are available when building a cross compiler. 
1260The <var>dir</var> argument specifies a directory which has the target include
1261files.  These include files will be copied into the <samp><span class="file">gcc</span></samp> install
1262directory.  <em>This option with the </em><var>dir</var><em> argument is required</em> when
1263building a cross compiler, if <samp><var>prefix</var><span class="file">/</span><var>target</var><span class="file">/sys-include</span></samp>
1264doesn't pre-exist.  If <samp><var>prefix</var><span class="file">/</span><var>target</var><span class="file">/sys-include</span></samp> does
1265pre-exist, the <var>dir</var> argument may be omitted.  <samp><span class="command">fixincludes</span></samp>
1266will be run on these files to make them compatible with GCC.
1267
1268     <br><dt><code>--without-headers</code><dd>Tells GCC not use any target headers from a libc when building a cross
1269compiler.  When crossing to GNU/Linux, you need the headers so GCC
1270can build the exception handling for libgcc.
1271
1272     <br><dt><code>--with-libs</code><dt><code>--with-libs="</code><var>dir1</var> <var>dir2</var><code> ... </code><var>dirN</var><code>"</code><dd>Deprecated in favor of <samp><span class="option">--with-sysroot</span></samp>. 
1273Specifies a list of directories which contain the target runtime
1274libraries.  These libraries will be copied into the <samp><span class="file">gcc</span></samp> install
1275directory.  If the directory list is omitted, this option has no
1276effect.
1277
1278     <br><dt><code>--with-newlib</code><dd>Specifies that &lsquo;<samp><span class="samp">newlib</span></samp>&rsquo; is
1279being used as the target C library.  This causes <code>__eprintf</code> to be
1280omitted from <samp><span class="file">libgcc.a</span></samp> on the assumption that it will be provided by
1281&lsquo;<samp><span class="samp">newlib</span></samp>&rsquo;.
1282
1283     <br><dt><code>--with-avrlibc</code><dd>Specifies that &lsquo;<samp><span class="samp">AVR-Libc</span></samp>&rsquo; is
1284being used as the target C library.  This causes float support
1285functions like <code>__addsf3</code> to be omitted from <samp><span class="file">libgcc.a</span></samp> on
1286the assumption that it will be provided by <samp><span class="file">libm.a</span></samp>.  For more
1287technical details, cf. <a href="http://gcc.gnu.org/PR54461">PR54461</a>. 
1288This option is only supported for the AVR target.  It is not supported for
1289RTEMS configurations, which currently use newlib.  The option is
1290supported since version 4.7.2 and is the default in 4.8.0 and newer.
1291
1292     <br><dt><code>--with-nds32-lib=</code><var>library</var><dd>Specifies that <var>library</var> setting is used for building <samp><span class="file">libgcc.a</span></samp>. 
1293Currently, the valid <var>library</var> is &lsquo;<samp><span class="samp">newlib</span></samp>&rsquo; or &lsquo;<samp><span class="samp">mculib</span></samp>&rsquo;. 
1294This option is only supported for the NDS32 target.
1295
1296     <br><dt><code>--with-build-time-tools=</code><var>dir</var><dd>Specifies where to find the set of target tools (assembler, linker, etc.) 
1297that will be used while building GCC itself.  This option can be useful
1298if the directory layouts are different between the system you are building
1299GCC on, and the system where you will deploy it.
1300
1301     <p>For example, on an &lsquo;<samp><span class="samp">ia64-hp-hpux</span></samp>&rsquo; system, you may have the GNU
1302assembler and linker in <samp><span class="file">/usr/bin</span></samp>, and the native tools in a
1303different path, and build a toolchain that expects to find the
1304native tools in <samp><span class="file">/usr/bin</span></samp>.
1305
1306     <p>When you use this option, you should ensure that <var>dir</var> includes
1307<samp><span class="command">ar</span></samp>, <samp><span class="command">as</span></samp>, <samp><span class="command">ld</span></samp>, <samp><span class="command">nm</span></samp>,
1308<samp><span class="command">ranlib</span></samp> and <samp><span class="command">strip</span></samp> if necessary, and possibly
1309<samp><span class="command">objdump</span></samp>.  Otherwise, GCC may use an inconsistent set of
1310tools. 
1311</dl>
1312
1313<h5 class="subsubheading"><a name="TOC4"></a>Overriding <samp><span class="command">configure</span></samp> test results</h5>
1314
1315<p>Sometimes, it might be necessary to override the result of some
1316<samp><span class="command">configure</span></samp> test, for example in order to ease porting to a new
1317system or work around a bug in a test.  The toplevel <samp><span class="command">configure</span></samp>
1318script provides three variables for this:
1319
1320     <dl>
1321<dt><code>build_configargs</code><dd><a name="index-g_t_0040code_007bbuild_005fconfigargs_007d-3"></a>The contents of this variable is passed to all build <samp><span class="command">configure</span></samp>
1322scripts.
1323
1324     <br><dt><code>host_configargs</code><dd><a name="index-g_t_0040code_007bhost_005fconfigargs_007d-4"></a>The contents of this variable is passed to all host <samp><span class="command">configure</span></samp>
1325scripts.
1326
1327     <br><dt><code>target_configargs</code><dd><a name="index-g_t_0040code_007btarget_005fconfigargs_007d-5"></a>The contents of this variable is passed to all target <samp><span class="command">configure</span></samp>
1328scripts.
1329
1330   </dl>
1331
1332   <p>In order to avoid shell and <samp><span class="command">make</span></samp> quoting issues for complex
1333overrides, you can pass a setting for <samp><span class="env">CONFIG_SITE</span></samp> and set
1334variables in the site file.
1335
1336<h4 class="subheading"><a name="TOC5"></a>Java-Specific Options</h4>
1337
1338<p>The following option applies to the build of the Java front end.
1339
1340     <dl>
1341<dt><code>--disable-libgcj</code><dd>Specify that the run-time libraries
1342used by GCJ should not be built.  This is useful in case you intend
1343to use GCJ with some other run-time, or you're going to install it
1344separately, or it just happens not to build on your particular
1345machine.  In general, if the Java front end is enabled, the GCJ
1346libraries will be enabled too, unless they're known to not work on
1347the target platform.  If GCJ is enabled but &lsquo;<samp><span class="samp">libgcj</span></samp>&rsquo; isn't built, you
1348may need to port it; in this case, before modifying the top-level
1349<samp><span class="file">configure.ac</span></samp> so that &lsquo;<samp><span class="samp">libgcj</span></samp>&rsquo; is enabled by default on this platform,
1350you may use <samp><span class="option">--enable-libgcj</span></samp> to override the default.
1351
1352   </dl>
1353
1354   <p>The following options apply to building &lsquo;<samp><span class="samp">libgcj</span></samp>&rsquo;.
1355
1356<h5 class="subsubheading"><a name="TOC6"></a>General Options</h5>
1357
1358     <dl>
1359<dt><code>--enable-java-maintainer-mode</code><dd>By default the &lsquo;<samp><span class="samp">libjava</span></samp>&rsquo; build will not attempt to compile the
1360<samp><span class="file">.java</span></samp> source files to <samp><span class="file">.class</span></samp>.  Instead, it will use the
1361<samp><span class="file">.class</span></samp> files from the source tree.  If you use this option you
1362must have executables named <samp><span class="command">ecj1</span></samp> and <samp><span class="command">gjavah</span></samp> in your path
1363for use by the build.  You must use this option if you intend to
1364modify any <samp><span class="file">.java</span></samp> files in <samp><span class="file">libjava</span></samp>.
1365
1366     <br><dt><code>--with-java-home=</code><var>dirname</var><dd>This &lsquo;<samp><span class="samp">libjava</span></samp>&rsquo; option overrides the default value of the
1367&lsquo;<samp><span class="samp">java.home</span></samp>&rsquo; system property.  It is also used to set
1368&lsquo;<samp><span class="samp">sun.boot.class.path</span></samp>&rsquo; to <samp><var>dirname</var><span class="file">/lib/rt.jar</span></samp>.  By
1369default &lsquo;<samp><span class="samp">java.home</span></samp>&rsquo; is set to <samp><var>prefix</var></samp> and
1370&lsquo;<samp><span class="samp">sun.boot.class.path</span></samp>&rsquo; to
1371<samp><var>datadir</var><span class="file">/java/libgcj-</span><var>version</var><span class="file">.jar</span></samp>.
1372
1373     <br><dt><code>--with-ecj-jar=</code><var>filename</var><dd>This option can be used to specify the location of an external jar
1374file containing the Eclipse Java compiler.  A specially modified
1375version of this compiler is used by <samp><span class="command">gcj</span></samp> to parse
1376<samp><span class="file">.java</span></samp> source files.  If this option is given, the
1377&lsquo;<samp><span class="samp">libjava</span></samp>&rsquo; build will create and install an <samp><span class="file">ecj1</span></samp> executable
1378which uses this jar file at runtime.
1379
1380     <p>If this option is not given, but an <samp><span class="file">ecj.jar</span></samp> file is found in
1381the topmost source tree at configure time, then the &lsquo;<samp><span class="samp">libgcj</span></samp>&rsquo;
1382build will create and install <samp><span class="file">ecj1</span></samp>, and will also install the
1383discovered <samp><span class="file">ecj.jar</span></samp> into a suitable place in the install tree.
1384
1385     <p>If <samp><span class="file">ecj1</span></samp> is not installed, then the user will have to supply one
1386on his path in order for <samp><span class="command">gcj</span></samp> to properly parse <samp><span class="file">.java</span></samp>
1387source files.  A suitable jar is available from
1388<a href="ftp://sourceware.org/pub/java/">ftp://sourceware.org/pub/java/</a>.
1389
1390     <br><dt><code>--disable-getenv-properties</code><dd>Don't set system properties from <samp><span class="env">GCJ_PROPERTIES</span></samp>.
1391
1392     <br><dt><code>--enable-hash-synchronization</code><dd>Use a global hash table for monitor locks.  Ordinarily,
1393&lsquo;<samp><span class="samp">libgcj</span></samp>&rsquo;'s &lsquo;<samp><span class="samp">configure</span></samp>&rsquo; script automatically makes
1394the correct choice for this option for your platform.  Only use
1395this if you know you need the library to be configured differently.
1396
1397     <br><dt><code>--enable-interpreter</code><dd>Enable the Java interpreter.  The interpreter is automatically
1398enabled by default on all platforms that support it.  This option
1399is really only useful if you want to disable the interpreter
1400(using <samp><span class="option">--disable-interpreter</span></samp>).
1401
1402     <br><dt><code>--disable-java-net</code><dd>Disable java.net.  This disables the native part of java.net only,
1403using non-functional stubs for native method implementations.
1404
1405     <br><dt><code>--disable-jvmpi</code><dd>Disable JVMPI support.
1406
1407     <br><dt><code>--disable-libgcj-bc</code><dd>Disable BC ABI compilation of certain parts of libgcj.  By default,
1408some portions of libgcj are compiled with <samp><span class="option">-findirect-dispatch</span></samp>
1409and <samp><span class="option">-fno-indirect-classes</span></samp>, allowing them to be overridden at
1410run-time.
1411
1412     <p>If <samp><span class="option">--disable-libgcj-bc</span></samp> is specified, libgcj is built without
1413these options.  This allows the compile-time linker to resolve
1414dependencies when statically linking to libgcj.  However it makes it
1415impossible to override the affected portions of libgcj at run-time.
1416
1417     <br><dt><code>--enable-reduced-reflection</code><dd>Build most of libgcj with <samp><span class="option">-freduced-reflection</span></samp>.  This reduces
1418the size of libgcj at the expense of not being able to do accurate
1419reflection on the classes it contains.  This option is safe if you
1420know that code using libgcj will never use reflection on the standard
1421runtime classes in libgcj (including using serialization, RMI or CORBA).
1422
1423     <br><dt><code>--with-ecos</code><dd>Enable runtime eCos target support.
1424
1425     <br><dt><code>--without-libffi</code><dd>Don't use &lsquo;<samp><span class="samp">libffi</span></samp>&rsquo;.  This will disable the interpreter and JNI
1426support as well, as these require &lsquo;<samp><span class="samp">libffi</span></samp>&rsquo; to work.
1427
1428     <br><dt><code>--enable-libgcj-debug</code><dd>Enable runtime debugging code.
1429
1430     <br><dt><code>--enable-libgcj-multifile</code><dd>If specified, causes all <samp><span class="file">.java</span></samp> source files to be
1431compiled into <samp><span class="file">.class</span></samp> files in one invocation of
1432&lsquo;<samp><span class="samp">gcj</span></samp>&rsquo;.  This can speed up build time, but is more
1433resource-intensive.  If this option is unspecified or
1434disabled, &lsquo;<samp><span class="samp">gcj</span></samp>&rsquo; is invoked once for each <samp><span class="file">.java</span></samp>
1435file to compile into a <samp><span class="file">.class</span></samp> file.
1436
1437     <br><dt><code>--with-libiconv-prefix=DIR</code><dd>Search for libiconv in <samp><span class="file">DIR/include</span></samp> and <samp><span class="file">DIR/lib</span></samp>.
1438
1439     <br><dt><code>--with-system-zlib</code><dd>Use installed &lsquo;<samp><span class="samp">zlib</span></samp>&rsquo; rather than that included with GCC.
1440
1441     <br><dt><code>--with-win32-nlsapi=ansi, unicows or unicode</code><dd>Indicates how MinGW &lsquo;<samp><span class="samp">libgcj</span></samp>&rsquo; translates between UNICODE
1442characters and the Win32 API.
1443
1444     <br><dt><code>--enable-java-home</code><dd>If enabled, this creates a JPackage compatible SDK environment during install. 
1445Note that if &ndash;enable-java-home is used, &ndash;with-arch-directory=ARCH must also
1446be specified.
1447
1448     <br><dt><code>--with-arch-directory=ARCH</code><dd>Specifies the name to use for the <samp><span class="file">jre/lib/ARCH</span></samp> directory in the SDK
1449environment created when &ndash;enable-java-home is passed. Typical names for this
1450directory include i386, amd64, ia64, etc.
1451
1452     <br><dt><code>--with-os-directory=DIR</code><dd>Specifies the OS directory for the SDK include directory. This is set to auto
1453detect, and is typically 'linux'.
1454
1455     <br><dt><code>--with-origin-name=NAME</code><dd>Specifies the JPackage origin name. This defaults to the 'gcj' in
1456java-1.5.0-gcj.
1457
1458     <br><dt><code>--with-arch-suffix=SUFFIX</code><dd>Specifies the suffix for the sdk directory. Defaults to the empty string. 
1459Examples include '.x86_64' in 'java-1.5.0-gcj-1.5.0.0.x86_64'.
1460
1461     <br><dt><code>--with-jvm-root-dir=DIR</code><dd>Specifies where to install the SDK. Default is $(prefix)/lib/jvm.
1462
1463     <br><dt><code>--with-jvm-jar-dir=DIR</code><dd>Specifies where to install jars. Default is $(prefix)/lib/jvm-exports.
1464
1465     <br><dt><code>--with-python-dir=DIR</code><dd>Specifies where to install the Python modules used for aot-compile. DIR should
1466not include the prefix used in installation. For example, if the Python modules
1467are to be installed in /usr/lib/python2.5/site-packages, then
1468&ndash;with-python-dir=/lib/python2.5/site-packages should be passed. If this is
1469not specified, then the Python modules are installed in $(prefix)/share/python.
1470
1471     <br><dt><code>--enable-aot-compile-rpm</code><dd>Adds aot-compile-rpm to the list of installed scripts.
1472
1473     <br><dt><code>--enable-browser-plugin</code><dd>Build the gcjwebplugin web browser plugin.
1474
1475     <br><dt><code>--enable-static-libjava</code><dd>Build static libraries in libjava. The default is to only build shared
1476libraries.
1477
1478          <dl>
1479<dt><code>ansi</code><dd>Use the single-byte <code>char</code> and the Win32 A functions natively,
1480translating to and from UNICODE when using these functions.  If
1481unspecified, this is the default.
1482
1483          <br><dt><code>unicows</code><dd>Use the <code>WCHAR</code> and Win32 W functions natively.  Adds
1484<code>-lunicows</code> to <samp><span class="file">libgcj.spec</span></samp> to link with &lsquo;<samp><span class="samp">libunicows</span></samp>&rsquo;. 
1485<samp><span class="file">unicows.dll</span></samp> needs to be deployed on Microsoft Windows 9X machines
1486running built executables.  <samp><span class="file">libunicows.a</span></samp>, an open-source
1487import library around Microsoft's <code>unicows.dll</code>, is obtained from
1488<a href="http://libunicows.sourceforge.net/">http://libunicows.sourceforge.net/</a>, which also gives details
1489on getting <samp><span class="file">unicows.dll</span></samp> from Microsoft.
1490
1491          <br><dt><code>unicode</code><dd>Use the <code>WCHAR</code> and Win32 W functions natively.  Does <em>not</em>
1492add <code>-lunicows</code> to <samp><span class="file">libgcj.spec</span></samp>.  The built executables will
1493only run on Microsoft Windows NT and above. 
1494</dl>
1495     </dl>
1496
1497<h5 class="subsubheading"><a name="TOC7"></a>AWT-Specific Options</h5>
1498
1499     <dl>
1500<dt><code>--with-x</code><dd>Use the X Window System.
1501
1502     <br><dt><code>--enable-java-awt=PEER(S)</code><dd>Specifies the AWT peer library or libraries to build alongside
1503&lsquo;<samp><span class="samp">libgcj</span></samp>&rsquo;.  If this option is unspecified or disabled, AWT
1504will be non-functional.  Current valid values are <samp><span class="option">gtk</span></samp> and
1505<samp><span class="option">xlib</span></samp>.  Multiple libraries should be separated by a
1506comma (i.e. <samp><span class="option">--enable-java-awt=gtk,xlib</span></samp>).
1507
1508     <br><dt><code>--enable-gtk-cairo</code><dd>Build the cairo Graphics2D implementation on GTK.
1509
1510     <br><dt><code>--enable-java-gc=TYPE</code><dd>Choose garbage collector.  Defaults to <samp><span class="option">boehm</span></samp> if unspecified.
1511
1512     <br><dt><code>--disable-gtktest</code><dd>Do not try to compile and run a test GTK+ program.
1513
1514     <br><dt><code>--disable-glibtest</code><dd>Do not try to compile and run a test GLIB program.
1515
1516     <br><dt><code>--with-libart-prefix=PFX</code><dd>Prefix where libart is installed (optional).
1517
1518     <br><dt><code>--with-libart-exec-prefix=PFX</code><dd>Exec prefix where libart is installed (optional).
1519
1520     <br><dt><code>--disable-libarttest</code><dd>Do not try to compile and run a test libart program.
1521
1522</dl>
1523
1524   <p><hr />
1525<p><a href="./index.html">Return to the GCC Installation page</a>
1526
1527<!-- ***Building**************************************************************** -->
1528<!-- ***Testing***************************************************************** -->
1529<!-- ***Final install*********************************************************** -->
1530<!-- ***Binaries**************************************************************** -->
1531<!-- ***Specific**************************************************************** -->
1532<!-- ***Old documentation****************************************************** -->
1533<!-- ***GFDL******************************************************************** -->
1534<!-- *************************************************************************** -->
1535<!-- Part 6 The End of the Document -->
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