1# serial 12 -*- Autoconf -*- 2# Enable extensions on systems that normally disable them. 3 4# Copyright (C) 2003, 2006-2012 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# 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# Remember that #undef in AH_VERBATIM gets replaced with #define by 34# AC_DEFINE. The goal here is to define all known feature-enabling 35# macros, then, if reports of conflicts are made, disable macros that 36# cause problems on some platforms (such as __EXTENSIONS__). 37AC_DEFUN_ONCE([AC_USE_SYSTEM_EXTENSIONS], 38[AC_BEFORE([$0], [AC_COMPILE_IFELSE])dnl 39AC_BEFORE([$0], [AC_RUN_IFELSE])dnl 40 41 AC_REQUIRE([AC_CANONICAL_HOST]) 42 43 AC_CHECK_HEADER([minix/config.h], [MINIX=yes], [MINIX=]) 44 if test "$MINIX" = yes; then 45 AC_DEFINE([_POSIX_SOURCE], [1], 46 [Define to 1 if you need to in order for 'stat' and other 47 things to work.]) 48 AC_DEFINE([_POSIX_1_SOURCE], [2], 49 [Define to 2 if the system does not provide POSIX.1 features 50 except with this defined.]) 51 AC_DEFINE([_MINIX], [1], 52 [Define to 1 if on MINIX.]) 53 fi 54 55 dnl HP-UX 11.11 defines mbstate_t only if _XOPEN_SOURCE is defined to 500, 56 dnl regardless of whether the flags -Ae or _D_HPUX_SOURCE=1 are already 57 dnl provided. 58 case "$host_os" in 59 hpux*) 60 AC_DEFINE([_XOPEN_SOURCE], [500], 61 [Define to 500 only on HP-UX.]) 62 ;; 63 esac 64 65 AH_VERBATIM([__EXTENSIONS__], 66[/* Enable extensions on AIX 3, Interix. */ 67#ifndef _ALL_SOURCE 68# undef _ALL_SOURCE 69#endif 70/* Enable general extensions on Mac OS X. */ 71#ifndef _DARWIN_C_SOURCE 72# undef _DARWIN_C_SOURCE 73#endif 74/* Enable GNU extensions on systems that have them. */ 75#ifndef _GNU_SOURCE 76# undef _GNU_SOURCE 77#endif 78/* Enable threading extensions on Solaris. */ 79#ifndef _POSIX_PTHREAD_SEMANTICS 80# undef _POSIX_PTHREAD_SEMANTICS 81#endif 82/* Enable extensions on HP NonStop. */ 83#ifndef _TANDEM_SOURCE 84# undef _TANDEM_SOURCE 85#endif 86/* Enable general extensions on Solaris. */ 87#ifndef __EXTENSIONS__ 88# undef __EXTENSIONS__ 89#endif 90]) 91 AC_CACHE_CHECK([whether it is safe to define __EXTENSIONS__], 92 [ac_cv_safe_to_define___extensions__], 93 [AC_COMPILE_IFELSE( 94 [AC_LANG_PROGRAM([[ 95# define __EXTENSIONS__ 1 96 ]AC_INCLUDES_DEFAULT])], 97 [ac_cv_safe_to_define___extensions__=yes], 98 [ac_cv_safe_to_define___extensions__=no])]) 99 test $ac_cv_safe_to_define___extensions__ = yes && 100 AC_DEFINE([__EXTENSIONS__]) 101 AC_DEFINE([_ALL_SOURCE]) 102 AC_DEFINE([_DARWIN_C_SOURCE]) 103 AC_DEFINE([_GNU_SOURCE]) 104 AC_DEFINE([_POSIX_PTHREAD_SEMANTICS]) 105 AC_DEFINE([_TANDEM_SOURCE]) 106])# AC_USE_SYSTEM_EXTENSIONS 107 108# gl_USE_SYSTEM_EXTENSIONS 109# ------------------------ 110# Enable extensions on systems that normally disable them, 111# typically due to standards-conformance issues. 112AC_DEFUN_ONCE([gl_USE_SYSTEM_EXTENSIONS], 113[ 114 dnl Require this macro before AC_USE_SYSTEM_EXTENSIONS. 115 dnl gnulib does not need it. But if it gets required by third-party macros 116 dnl after AC_USE_SYSTEM_EXTENSIONS is required, autoconf 2.62..2.63 emit a 117 dnl warning: "AC_COMPILE_IFELSE was called before AC_USE_SYSTEM_EXTENSIONS". 118 dnl Note: We can do this only for one of the macros AC_AIX, AC_GNU_SOURCE, 119 dnl AC_MINIX. If people still use AC_AIX or AC_MINIX, they are out of luck. 120 AC_REQUIRE([AC_GNU_SOURCE]) 121 122 AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS]) 123]) 124