1# serial 13 -*- Autoconf -*- 2# Enable extensions on systems that normally disable them. 3 4# Copyright (C) 2003, 2006-2014 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 git 10# Autoconf. Perhaps we can remove this once we can assume Autoconf 11# 2.70 or later everywhere, but since 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# If autoconf reports a warning 16# warning: AC_COMPILE_IFELSE was called before AC_USE_SYSTEM_EXTENSIONS 17# or warning: AC_RUN_IFELSE was called before AC_USE_SYSTEM_EXTENSIONS 18# the fix is 19# 1) to ensure that AC_USE_SYSTEM_EXTENSIONS is never directly invoked 20# but always AC_REQUIREd, 21# 2) to ensure that for each occurrence of 22# AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS]) 23# or 24# AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS]) 25# the corresponding gnulib module description has 'extensions' among 26# its dependencies. This will ensure that the gl_USE_SYSTEM_EXTENSIONS 27# invocation occurs in gl_EARLY, not in gl_INIT. 28 29# AC_USE_SYSTEM_EXTENSIONS 30# ------------------------ 31# Enable extensions on systems that normally disable them, 32# typically due to standards-conformance issues. 33# 34# Remember that #undef in AH_VERBATIM gets replaced with #define by 35# AC_DEFINE. The goal here is to define all known feature-enabling 36# macros, then, if reports of conflicts are made, disable macros that 37# cause problems on some platforms (such as __EXTENSIONS__). 38AC_DEFUN_ONCE([AC_USE_SYSTEM_EXTENSIONS], 39[AC_BEFORE([$0], [AC_COMPILE_IFELSE])dnl 40AC_BEFORE([$0], [AC_RUN_IFELSE])dnl 41 42 AC_CHECK_HEADER([minix/config.h], [MINIX=yes], [MINIX=]) 43 if test "$MINIX" = yes; then 44 AC_DEFINE([_POSIX_SOURCE], [1], 45 [Define to 1 if you need to in order for 'stat' and other 46 things to work.]) 47 AC_DEFINE([_POSIX_1_SOURCE], [2], 48 [Define to 2 if the system does not provide POSIX.1 features 49 except with this defined.]) 50 AC_DEFINE([_MINIX], [1], 51 [Define to 1 if on MINIX.]) 52 AC_DEFINE([_NETBSD_SOURCE], [1], 53 [Define to 1 to make NetBSD features available. MINIX 3 needs this.]) 54 fi 55 56dnl Use a different key than __EXTENSIONS__, as that name broke existing 57dnl configure.ac when using autoheader 2.62. 58 AH_VERBATIM([USE_SYSTEM_EXTENSIONS], 59[/* Enable extensions on AIX 3, Interix. */ 60#ifndef _ALL_SOURCE 61# undef _ALL_SOURCE 62#endif 63/* Enable general extensions on OS X. */ 64#ifndef _DARWIN_C_SOURCE 65# undef _DARWIN_C_SOURCE 66#endif 67/* Enable GNU extensions on systems that have them. */ 68#ifndef _GNU_SOURCE 69# undef _GNU_SOURCE 70#endif 71/* Enable threading extensions on Solaris. */ 72#ifndef _POSIX_PTHREAD_SEMANTICS 73# undef _POSIX_PTHREAD_SEMANTICS 74#endif 75/* Enable extensions on HP NonStop. */ 76#ifndef _TANDEM_SOURCE 77# undef _TANDEM_SOURCE 78#endif 79/* Enable X/Open extensions if necessary. HP-UX 11.11 defines 80 mbstate_t only if _XOPEN_SOURCE is defined to 500, regardless of 81 whether compiling with -Ae or -D_HPUX_SOURCE=1. */ 82#ifndef _XOPEN_SOURCE 83# undef _XOPEN_SOURCE 84#endif 85/* Enable general extensions on Solaris. */ 86#ifndef __EXTENSIONS__ 87# undef __EXTENSIONS__ 88#endif 89]) 90 AC_CACHE_CHECK([whether it is safe to define __EXTENSIONS__], 91 [ac_cv_safe_to_define___extensions__], 92 [AC_COMPILE_IFELSE( 93 [AC_LANG_PROGRAM([[ 94# define __EXTENSIONS__ 1 95 ]AC_INCLUDES_DEFAULT])], 96 [ac_cv_safe_to_define___extensions__=yes], 97 [ac_cv_safe_to_define___extensions__=no])]) 98 test $ac_cv_safe_to_define___extensions__ = yes && 99 AC_DEFINE([__EXTENSIONS__]) 100 AC_DEFINE([_ALL_SOURCE]) 101 AC_DEFINE([_DARWIN_C_SOURCE]) 102 AC_DEFINE([_GNU_SOURCE]) 103 AC_DEFINE([_POSIX_PTHREAD_SEMANTICS]) 104 AC_DEFINE([_TANDEM_SOURCE]) 105 AC_CACHE_CHECK([whether _XOPEN_SOURCE should be defined], 106 [ac_cv_should_define__xopen_source], 107 [ac_cv_should_define__xopen_source=no 108 AC_COMPILE_IFELSE( 109 [AC_LANG_PROGRAM([[ 110 #include <wchar.h> 111 mbstate_t x;]])], 112 [], 113 [AC_COMPILE_IFELSE( 114 [AC_LANG_PROGRAM([[ 115 #define _XOPEN_SOURCE 500 116 #include <wchar.h> 117 mbstate_t x;]])], 118 [ac_cv_should_define__xopen_source=yes])])]) 119 test $ac_cv_should_define__xopen_source = yes && 120 AC_DEFINE([_XOPEN_SOURCE], [500]) 121])# AC_USE_SYSTEM_EXTENSIONS 122 123# gl_USE_SYSTEM_EXTENSIONS 124# ------------------------ 125# Enable extensions on systems that normally disable them, 126# typically due to standards-conformance issues. 127AC_DEFUN_ONCE([gl_USE_SYSTEM_EXTENSIONS], 128[ 129 dnl Require this macro before AC_USE_SYSTEM_EXTENSIONS. 130 dnl gnulib does not need it. But if it gets required by third-party macros 131 dnl after AC_USE_SYSTEM_EXTENSIONS is required, autoconf 2.62..2.63 emit a 132 dnl warning: "AC_COMPILE_IFELSE was called before AC_USE_SYSTEM_EXTENSIONS". 133 dnl Note: We can do this only for one of the macros AC_AIX, AC_GNU_SOURCE, 134 dnl AC_MINIX. If people still use AC_AIX or AC_MINIX, they are out of luck. 135 AC_REQUIRE([AC_GNU_SOURCE]) 136 137 AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS]) 138]) 139