1# serial 8  -*- Autoconf -*-
2# Enable extensions on systems that normally disable them.
3
4# Copyright (C) 2003, 2006-2009 Free Software Foundation, Inc.
5# This file is free software; the Free Software Foundation
6# gives unlimited permission to copy and/or distribute it,
7# with or without modifications, as long as this notice is preserved.
8
9# This definition of AC_USE_SYSTEM_EXTENSIONS is stolen from CVS
10# Autoconf.  Perhaps we can remove this once we can assume Autoconf
11# 2.62 or later everywhere, but since CVS Autoconf mutates rapidly
12# enough in this area it's likely we'll need to redefine
13# AC_USE_SYSTEM_EXTENSIONS for quite some time.
14
15# AC_USE_SYSTEM_EXTENSIONS
16# ------------------------
17# Enable extensions on systems that normally disable them,
18# typically due to standards-conformance issues.
19# Remember that #undef in AH_VERBATIM gets replaced with #define by
20# AC_DEFINE.  The goal here is to define all known feature-enabling
21# macros, then, if reports of conflicts are made, disable macros that
22# cause problems on some platforms (such as __EXTENSIONS__).
23AC_DEFUN_ONCE([AC_USE_SYSTEM_EXTENSIONS],
24[AC_BEFORE([$0], [AC_COMPILE_IFELSE])dnl
25AC_BEFORE([$0], [AC_RUN_IFELSE])dnl
26
27  AC_REQUIRE([AC_CANONICAL_HOST])
28
29  AC_CHECK_HEADER([minix/config.h], [MINIX=yes], [MINIX=])
30  if test "$MINIX" = yes; then
31    AC_DEFINE([_POSIX_SOURCE], [1],
32      [Define to 1 if you need to in order for `stat' and other
33       things to work.])
34    AC_DEFINE([_POSIX_1_SOURCE], [2],
35      [Define to 2 if the system does not provide POSIX.1 features
36       except with this defined.])
37    AC_DEFINE([_MINIX], [1],
38      [Define to 1 if on MINIX.])
39  fi
40
41  dnl HP-UX 11.11 defines mbstate_t only if _XOPEN_SOURCE is defined to 500,
42  dnl regardless of whether the flags -Ae or _D_HPUX_SOURCE=1 are already
43  dnl provided.
44  case "$host_os" in
45    hpux*)
46      AC_DEFINE([_XOPEN_SOURCE], [500],
47        [Define to 500 only on HP-UX.])
48      ;;
49  esac
50
51  AH_VERBATIM([__EXTENSIONS__],
52[/* Enable extensions on AIX 3, Interix.  */
53#ifndef _ALL_SOURCE
54# undef _ALL_SOURCE
55#endif
56/* Enable GNU extensions on systems that have them.  */
57#ifndef _GNU_SOURCE
58# undef _GNU_SOURCE
59#endif
60/* Enable threading extensions on Solaris.  */
61#ifndef _POSIX_PTHREAD_SEMANTICS
62# undef _POSIX_PTHREAD_SEMANTICS
63#endif
64/* Enable extensions on HP NonStop.  */
65#ifndef _TANDEM_SOURCE
66# undef _TANDEM_SOURCE
67#endif
68/* Enable general extensions on Solaris.  */
69#ifndef __EXTENSIONS__
70# undef __EXTENSIONS__
71#endif
72])
73  AC_CACHE_CHECK([whether it is safe to define __EXTENSIONS__],
74    [ac_cv_safe_to_define___extensions__],
75    [AC_COMPILE_IFELSE(
76       [AC_LANG_PROGRAM([[
77#	  define __EXTENSIONS__ 1
78	  ]AC_INCLUDES_DEFAULT])],
79       [ac_cv_safe_to_define___extensions__=yes],
80       [ac_cv_safe_to_define___extensions__=no])])
81  test $ac_cv_safe_to_define___extensions__ = yes &&
82    AC_DEFINE([__EXTENSIONS__])
83  AC_DEFINE([_ALL_SOURCE])
84  AC_DEFINE([_GNU_SOURCE])
85  AC_DEFINE([_POSIX_PTHREAD_SEMANTICS])
86  AC_DEFINE([_TANDEM_SOURCE])
87])# AC_USE_SYSTEM_EXTENSIONS
88
89# gl_USE_SYSTEM_EXTENSIONS
90# ------------------------
91# Enable extensions on systems that normally disable them,
92# typically due to standards-conformance issues.
93AC_DEFUN_ONCE([gl_USE_SYSTEM_EXTENSIONS],
94[
95  dnl Require this macro before AC_USE_SYSTEM_EXTENSIONS.
96  dnl gnulib does not need it. But if it gets required by third-party macros
97  dnl after AC_USE_SYSTEM_EXTENSIONS is required, autoconf 2.62..2.63 emit a
98  dnl warning: "AC_COMPILE_IFELSE was called before AC_USE_SYSTEM_EXTENSIONS".
99  dnl Note: We can do this only for one of the macros AC_AIX, AC_GNU_SOURCE,
100  dnl AC_MINIX. If people still use AC_AIX or AC_MINIX, they are out of luck.
101  AC_REQUIRE([AC_GNU_SOURCE])
102
103  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
104])
105