1# serial 18  -*- Autoconf -*-
2# Enable extensions on systems that normally disable them.
3
4# Copyright (C) 2003, 2006-2020 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 macOS.  */
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 NetBSD extensions on NetBSD.  */
72#ifndef _NETBSD_SOURCE
73# undef _NETBSD_SOURCE
74#endif
75/* Enable OpenBSD extensions on NetBSD.  */
76#ifndef _OPENBSD_SOURCE
77# undef _OPENBSD_SOURCE
78#endif
79/* Enable threading extensions on Solaris.  */
80#ifndef _POSIX_PTHREAD_SEMANTICS
81# undef _POSIX_PTHREAD_SEMANTICS
82#endif
83/* Enable extensions specified by ISO/IEC TS 18661-5:2014.  */
84#ifndef __STDC_WANT_IEC_60559_ATTRIBS_EXT__
85# undef __STDC_WANT_IEC_60559_ATTRIBS_EXT__
86#endif
87/* Enable extensions specified by ISO/IEC TS 18661-1:2014.  */
88#ifndef __STDC_WANT_IEC_60559_BFP_EXT__
89# undef __STDC_WANT_IEC_60559_BFP_EXT__
90#endif
91/* Enable extensions specified by ISO/IEC TS 18661-2:2015.  */
92#ifndef __STDC_WANT_IEC_60559_DFP_EXT__
93# undef __STDC_WANT_IEC_60559_DFP_EXT__
94#endif
95/* Enable extensions specified by ISO/IEC TS 18661-4:2015.  */
96#ifndef __STDC_WANT_IEC_60559_FUNCS_EXT__
97# undef __STDC_WANT_IEC_60559_FUNCS_EXT__
98#endif
99/* Enable extensions specified by ISO/IEC TS 18661-3:2015.  */
100#ifndef __STDC_WANT_IEC_60559_TYPES_EXT__
101# undef __STDC_WANT_IEC_60559_TYPES_EXT__
102#endif
103/* Enable extensions specified by ISO/IEC TR 24731-2:2010.  */
104#ifndef __STDC_WANT_LIB_EXT2__
105# undef __STDC_WANT_LIB_EXT2__
106#endif
107/* Enable extensions specified by ISO/IEC 24747:2009.  */
108#ifndef __STDC_WANT_MATH_SPEC_FUNCS__
109# undef __STDC_WANT_MATH_SPEC_FUNCS__
110#endif
111/* Enable extensions on HP NonStop.  */
112#ifndef _TANDEM_SOURCE
113# undef _TANDEM_SOURCE
114#endif
115/* Enable X/Open extensions if necessary.  HP-UX 11.11 defines
116   mbstate_t only if _XOPEN_SOURCE is defined to 500, regardless of
117   whether compiling with -Ae or -D_HPUX_SOURCE=1.  */
118#ifndef _XOPEN_SOURCE
119# undef _XOPEN_SOURCE
120#endif
121/* Enable X/Open compliant socket functions that do not require linking
122   with -lxnet on HP-UX 11.11.  */
123#ifndef _HPUX_ALT_XOPEN_SOCKET_API
124# undef _HPUX_ALT_XOPEN_SOCKET_API
125#endif
126/* Enable general extensions on Solaris.  */
127#ifndef __EXTENSIONS__
128# undef __EXTENSIONS__
129#endif
130])
131  AC_CACHE_CHECK([whether it is safe to define __EXTENSIONS__],
132    [ac_cv_safe_to_define___extensions__],
133    [AC_COMPILE_IFELSE(
134       [AC_LANG_PROGRAM([[
135#         define __EXTENSIONS__ 1
136          ]AC_INCLUDES_DEFAULT])],
137       [ac_cv_safe_to_define___extensions__=yes],
138       [ac_cv_safe_to_define___extensions__=no])])
139  test $ac_cv_safe_to_define___extensions__ = yes &&
140    AC_DEFINE([__EXTENSIONS__])
141  AC_DEFINE([_ALL_SOURCE])
142  AC_DEFINE([_DARWIN_C_SOURCE])
143  AC_DEFINE([_GNU_SOURCE])
144  AC_DEFINE([_NETBSD_SOURCE])
145  AC_DEFINE([_OPENBSD_SOURCE])
146  AC_DEFINE([_POSIX_PTHREAD_SEMANTICS])
147  AC_DEFINE([__STDC_WANT_IEC_60559_ATTRIBS_EXT__])
148  AC_DEFINE([__STDC_WANT_IEC_60559_BFP_EXT__])
149  AC_DEFINE([__STDC_WANT_IEC_60559_DFP_EXT__])
150  AC_DEFINE([__STDC_WANT_IEC_60559_FUNCS_EXT__])
151  AC_DEFINE([__STDC_WANT_IEC_60559_TYPES_EXT__])
152  AC_DEFINE([__STDC_WANT_LIB_EXT2__])
153  AC_DEFINE([__STDC_WANT_MATH_SPEC_FUNCS__])
154  AC_DEFINE([_TANDEM_SOURCE])
155  AC_CACHE_CHECK([whether _XOPEN_SOURCE should be defined],
156    [ac_cv_should_define__xopen_source],
157    [ac_cv_should_define__xopen_source=no
158     AC_COMPILE_IFELSE(
159       [AC_LANG_PROGRAM([[
160          #include <wchar.h>
161          mbstate_t x;]])],
162       [],
163       [AC_COMPILE_IFELSE(
164          [AC_LANG_PROGRAM([[
165             #define _XOPEN_SOURCE 500
166             #include <wchar.h>
167             mbstate_t x;]])],
168          [ac_cv_should_define__xopen_source=yes])])])
169  test $ac_cv_should_define__xopen_source = yes &&
170    AC_DEFINE([_XOPEN_SOURCE], [500])
171  AC_DEFINE([_HPUX_ALT_XOPEN_SOCKET_API])
172])# AC_USE_SYSTEM_EXTENSIONS
173
174# gl_USE_SYSTEM_EXTENSIONS
175# ------------------------
176# Enable extensions on systems that normally disable them,
177# typically due to standards-conformance issues.
178AC_DEFUN_ONCE([gl_USE_SYSTEM_EXTENSIONS],
179[
180  dnl Require this macro before AC_USE_SYSTEM_EXTENSIONS.
181  dnl gnulib does not need it. But if it gets required by third-party macros
182  dnl after AC_USE_SYSTEM_EXTENSIONS is required, autoconf 2.62..2.63 emit a
183  dnl warning: "AC_COMPILE_IFELSE was called before AC_USE_SYSTEM_EXTENSIONS".
184  dnl Note: We can do this only for one of the macros AC_AIX, AC_GNU_SOURCE,
185  dnl AC_MINIX. If people still use AC_AIX or AC_MINIX, they are out of luck.
186  AC_REQUIRE([AC_GNU_SOURCE])
187
188  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
189])
190