1# serial 6  -*- Autoconf -*-
2# Enable extensions on systems that normally disable them.
3
4# Copyright (C) 2003, 2006, 2007, 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
15m4_version_prereq([2.62],, [
16
17# AC_USE_SYSTEM_EXTENSIONS
18# ------------------------
19# Enable extensions on systems that normally disable them,
20# typically due to standards-conformance issues.
21# Remember that #undef in AH_VERBATIM gets replaced with #define by
22# AC_DEFINE.  The goal here is to define all known feature-enabling
23# macros, then, if reports of conflicts are made, disable macros that
24# cause problems on some platforms (such as __EXTENSIONS__).
25AC_DEFUN([AC_USE_SYSTEM_EXTENSIONS],
26[AC_BEFORE([$0], [AC_COMPILE_IFELSE])dnl
27AC_BEFORE([$0], [AC_RUN_IFELSE])dnl
28
29  AC_CHECK_HEADER([minix/config.h], [MINIX=yes], [MINIX=])
30  if test "$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  AH_VERBATIM([__EXTENSIONS__],
42[/* Enable extensions on AIX 3, Interix.  */
43#ifndef _ALL_SOURCE
44# undef _ALL_SOURCE
45#endif
46/* Enable GNU extensions on systems that have them.  */
47#ifndef _GNU_SOURCE
48# undef _GNU_SOURCE
49#endif
50/* Enable threading extensions on Solaris.  */
51#ifndef _POSIX_PTHREAD_SEMANTICS
52# undef _POSIX_PTHREAD_SEMANTICS
53#endif
54/* Enable extensions on HP NonStop.  */
55#ifndef _TANDEM_SOURCE
56# undef _TANDEM_SOURCE
57#endif
58/* Enable general extensions on Solaris.  */
59#ifndef __EXTENSIONS__
60# undef __EXTENSIONS__
61#endif
62])
63  AC_CACHE_CHECK([whether it is safe to define __EXTENSIONS__],
64    [ac_cv_safe_to_define___extensions__],
65    [AC_COMPILE_IFELSE(
66       [AC_LANG_PROGRAM([
67#	  define __EXTENSIONS__ 1
68	  AC_INCLUDES_DEFAULT])],
69       [ac_cv_safe_to_define___extensions__=yes],
70       [ac_cv_safe_to_define___extensions__=no])])
71  test $ac_cv_safe_to_define___extensions__ = yes &&
72    AC_DEFINE([__EXTENSIONS__])
73  AC_DEFINE([_ALL_SOURCE])
74  AC_DEFINE([_GNU_SOURCE])
75  AC_DEFINE([_POSIX_PTHREAD_SEMANTICS])
76  AC_DEFINE([_TANDEM_SOURCE])
77])# AC_USE_SYSTEM_EXTENSIONS
78
79])
80