1 # serial 13 -*- Autoconf -*-
2 # Enable extensions on systems that normally disable them.
4 # Copyright (C) 2003, 2006-2013 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.
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.
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
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])
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.
29 # AC_USE_SYSTEM_EXTENSIONS
30 # ------------------------
31 # Enable extensions on systems that normally disable them,
32 # typically due to standards-conformance issues.
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__).
38 AC_DEFUN_ONCE([AC_USE_SYSTEM_EXTENSIONS],
39 [AC_BEFORE([$0], [AC_COMPILE_IFELSE])dnl
40 AC_BEFORE([$0], [AC_RUN_IFELSE])dnl
42 AC_CHECK_HEADER([minix/config.h], [MINIX=yes], [MINIX=])
43 if test "$MINIX" = yes; then
44 AC_DEFINE([_POSIX_SOURCE], [1],
45 [Define to 1 if you need to in order for 'stat' and other
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.])
56 dnl Use a different key than __EXTENSIONS__, as that name broke existing
57 dnl configure.ac when using autoheader 2.62.
58 AH_VERBATIM([USE_SYSTEM_EXTENSIONS],
59 [/* Enable extensions on AIX 3, Interix. */
63 /* Enable general extensions on OS X. */
64 #ifndef _DARWIN_C_SOURCE
65 # undef _DARWIN_C_SOURCE
67 /* Enable GNU extensions on systems that have them. */
71 /* HP-UX 11.11 defines mbstate_t only if _XOPEN_SOURCE is defined to 500,
72 regardless of whether compiling with -Ae or -D_HPUX_SOURCE=1. */
74 # define _XOPEN_SOURCE 500
76 /* Enable threading extensions on Solaris. */
77 #ifndef _POSIX_PTHREAD_SEMANTICS
78 # undef _POSIX_PTHREAD_SEMANTICS
80 /* Enable extensions on HP NonStop. */
81 #ifndef _TANDEM_SOURCE
82 # undef _TANDEM_SOURCE
84 /* Enable general extensions on Solaris. */
85 #ifndef __EXTENSIONS__
86 # undef __EXTENSIONS__
89 AC_CACHE_CHECK([whether it is safe to define __EXTENSIONS__],
90 [ac_cv_safe_to_define___extensions__],
93 # define __EXTENSIONS__ 1
94 ]AC_INCLUDES_DEFAULT])],
95 [ac_cv_safe_to_define___extensions__=yes],
96 [ac_cv_safe_to_define___extensions__=no])])
97 test $ac_cv_safe_to_define___extensions__ = yes &&
98 AC_DEFINE([__EXTENSIONS__])
99 AC_DEFINE([_ALL_SOURCE])
100 AC_DEFINE([_DARWIN_C_SOURCE])
101 AC_DEFINE([_GNU_SOURCE])
102 AC_DEFINE([_POSIX_PTHREAD_SEMANTICS])
103 AC_DEFINE([_TANDEM_SOURCE])
104 ])# AC_USE_SYSTEM_EXTENSIONS
106 # gl_USE_SYSTEM_EXTENSIONS
107 # ------------------------
108 # Enable extensions on systems that normally disable them,
109 # typically due to standards-conformance issues.
110 AC_DEFUN_ONCE([gl_USE_SYSTEM_EXTENSIONS],
112 dnl Require this macro before AC_USE_SYSTEM_EXTENSIONS.
113 dnl gnulib does not need it. But if it gets required by third-party macros
114 dnl after AC_USE_SYSTEM_EXTENSIONS is required, autoconf 2.62..2.63 emit a
115 dnl warning: "AC_COMPILE_IFELSE was called before AC_USE_SYSTEM_EXTENSIONS".
116 dnl Note: We can do this only for one of the macros AC_AIX, AC_GNU_SOURCE,
117 dnl AC_MINIX. If people still use AC_AIX or AC_MINIX, they are out of luck.
118 AC_REQUIRE([AC_GNU_SOURCE])
120 AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])