| 1 | # serial 22  -*- Autoconf -*-
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| 2 | # Enable extensions on systems that normally disable them.
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| 3 | 
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| 4 | # Copyright (C) 2003, 2006-2022 Free Software Foundation, Inc.
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| 5 | # This file is free software; the Free Software Foundation
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| 6 | # gives unlimited permission to copy and/or distribute it,
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| 7 | # with or without modifications, as long as this notice is preserved.
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| 8 | 
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| 9 | dnl Define to empty for the benefit of Autoconf 2.69 and earlier, so that
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| 10 | dnl AC_USE_SYSTEM_EXTENSIONS (below) can be used unchanged from Autoconf 2.70+.
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| 11 | m4_ifndef([AC_CHECK_INCLUDES_DEFAULT],
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| 12 |   [AC_DEFUN([AC_CHECK_INCLUDES_DEFAULT], [])])
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| 13 | 
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| 14 | # This definition of AC_USE_SYSTEM_EXTENSIONS is stolen from git
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| 15 | # Autoconf.  Perhaps we can remove this once we can assume Autoconf
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| 16 | # is recent-enough everywhere, but since Autoconf mutates rapidly
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| 17 | # enough in this area it's likely we'll need to redefine
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| 18 | # AC_USE_SYSTEM_EXTENSIONS for quite some time.
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| 19 | 
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| 20 | # If autoconf reports a warning
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| 21 | #     warning: AC_COMPILE_IFELSE was called before AC_USE_SYSTEM_EXTENSIONS
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| 22 | # or  warning: AC_RUN_IFELSE was called before AC_USE_SYSTEM_EXTENSIONS
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| 23 | # the fix is
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| 24 | #   1) to ensure that AC_USE_SYSTEM_EXTENSIONS is never directly invoked
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| 25 | #      but always AC_REQUIREd,
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| 26 | #   2) to ensure that for each occurrence of
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| 27 | #        AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
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| 28 | #      or
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| 29 | #        AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
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| 30 | #      the corresponding gnulib module description has 'extensions' among
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| 31 | #      its dependencies. This will ensure that the gl_USE_SYSTEM_EXTENSIONS
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| 32 | #      invocation occurs in gl_EARLY, not in gl_INIT.
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| 33 | 
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| 34 | m4_version_prereq([2.70.1], [], [
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| 35 | 
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| 36 | # AC_USE_SYSTEM_EXTENSIONS
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| 37 | # ------------------------
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| 38 | # Enable extensions on systems that normally disable them,
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| 39 | # typically due to standards-conformance issues.
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| 40 | # We unconditionally define as many of the known feature-enabling
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| 41 | # as possible, reserving conditional behavior for macros that are
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| 42 | # known to cause problems on some platforms (such as __EXTENSIONS__).
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| 43 | AC_DEFUN_ONCE([AC_USE_SYSTEM_EXTENSIONS],
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| 44 | [AC_BEFORE([$0], [AC_PREPROC_IFELSE])dnl
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| 45 | AC_BEFORE([$0], [AC_COMPILE_IFELSE])dnl
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| 46 | AC_BEFORE([$0], [AC_LINK_IFELSE])dnl
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| 47 | AC_BEFORE([$0], [AC_RUN_IFELSE])dnl
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| 48 | AC_BEFORE([$0], [AC_CHECK_INCLUDES_DEFAULT])dnl
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| 49 | dnl #undef in AH_VERBATIM gets replaced with #define by AC_DEFINE.
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| 50 | dnl Use a different key than __EXTENSIONS__, as that name broke existing
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| 51 | dnl configure.ac when using autoheader 2.62.
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| 52 | dnl The macros below are in alphabetical order ignoring leading _ or __
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| 53 | dnl prefixes.
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| 54 | AH_VERBATIM([USE_SYSTEM_EXTENSIONS],
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| 55 | [/* Enable extensions on AIX 3, Interix.  */
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| 56 | #ifndef _ALL_SOURCE
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| 57 | # undef _ALL_SOURCE
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| 58 | #endif
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| 59 | /* Enable general extensions on macOS.  */
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| 60 | #ifndef _DARWIN_C_SOURCE
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| 61 | # undef _DARWIN_C_SOURCE
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| 62 | #endif
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| 63 | /* Enable general extensions on Solaris.  */
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| 64 | #ifndef __EXTENSIONS__
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| 65 | # undef __EXTENSIONS__
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| 66 | #endif
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| 67 | /* Enable GNU extensions on systems that have them.  */
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| 68 | #ifndef _GNU_SOURCE
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| 69 | # undef _GNU_SOURCE
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| 70 | #endif
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| 71 | /* Enable X/Open compliant socket functions that do not require linking
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| 72 |    with -lxnet on HP-UX 11.11.  */
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| 73 | #ifndef _HPUX_ALT_XOPEN_SOCKET_API
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| 74 | # undef _HPUX_ALT_XOPEN_SOCKET_API
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| 75 | #endif
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| 76 | /* Identify the host operating system as Minix.
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| 77 |    This macro does not affect the system headers' behavior.
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| 78 |    A future release of Autoconf may stop defining this macro.  */
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| 79 | #ifndef _MINIX
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| 80 | # undef _MINIX
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| 81 | #endif
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| 82 | /* Enable general extensions on NetBSD.
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| 83 |    Enable NetBSD compatibility extensions on Minix.  */
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| 84 | #ifndef _NETBSD_SOURCE
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| 85 | # undef _NETBSD_SOURCE
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| 86 | #endif
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| 87 | /* Enable OpenBSD compatibility extensions on NetBSD.
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| 88 |    Oddly enough, this does nothing on OpenBSD.  */
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| 89 | #ifndef _OPENBSD_SOURCE
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| 90 | # undef _OPENBSD_SOURCE
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| 91 | #endif
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| 92 | /* Define to 1 if needed for POSIX-compatible behavior.  */
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| 93 | #ifndef _POSIX_SOURCE
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| 94 | # undef _POSIX_SOURCE
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| 95 | #endif
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| 96 | /* Define to 2 if needed for POSIX-compatible behavior.  */
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| 97 | #ifndef _POSIX_1_SOURCE
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| 98 | # undef _POSIX_1_SOURCE
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| 99 | #endif
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| 100 | /* Enable POSIX-compatible threading on Solaris.  */
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| 101 | #ifndef _POSIX_PTHREAD_SEMANTICS
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| 102 | # undef _POSIX_PTHREAD_SEMANTICS
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| 103 | #endif
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| 104 | /* Enable extensions specified by ISO/IEC TS 18661-5:2014.  */
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| 105 | #ifndef __STDC_WANT_IEC_60559_ATTRIBS_EXT__
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| 106 | # undef __STDC_WANT_IEC_60559_ATTRIBS_EXT__
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| 107 | #endif
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| 108 | /* Enable extensions specified by ISO/IEC TS 18661-1:2014.  */
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| 109 | #ifndef __STDC_WANT_IEC_60559_BFP_EXT__
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| 110 | # undef __STDC_WANT_IEC_60559_BFP_EXT__
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| 111 | #endif
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| 112 | /* Enable extensions specified by ISO/IEC TS 18661-2:2015.  */
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| 113 | #ifndef __STDC_WANT_IEC_60559_DFP_EXT__
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| 114 | # undef __STDC_WANT_IEC_60559_DFP_EXT__
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| 115 | #endif
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| 116 | /* Enable extensions specified by ISO/IEC TS 18661-4:2015.  */
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| 117 | #ifndef __STDC_WANT_IEC_60559_FUNCS_EXT__
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| 118 | # undef __STDC_WANT_IEC_60559_FUNCS_EXT__
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| 119 | #endif
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| 120 | /* Enable extensions specified by ISO/IEC TS 18661-3:2015.  */
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| 121 | #ifndef __STDC_WANT_IEC_60559_TYPES_EXT__
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| 122 | # undef __STDC_WANT_IEC_60559_TYPES_EXT__
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| 123 | #endif
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| 124 | /* Enable extensions specified by ISO/IEC TR 24731-2:2010.  */
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| 125 | #ifndef __STDC_WANT_LIB_EXT2__
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| 126 | # undef __STDC_WANT_LIB_EXT2__
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| 127 | #endif
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| 128 | /* Enable extensions specified by ISO/IEC 24747:2009.  */
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| 129 | #ifndef __STDC_WANT_MATH_SPEC_FUNCS__
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| 130 | # undef __STDC_WANT_MATH_SPEC_FUNCS__
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| 131 | #endif
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| 132 | /* Enable extensions on HP NonStop.  */
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| 133 | #ifndef _TANDEM_SOURCE
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| 134 | # undef _TANDEM_SOURCE
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| 135 | #endif
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| 136 | /* Enable X/Open extensions.  Define to 500 only if necessary
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| 137 |    to make mbstate_t available.  */
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| 138 | #ifndef _XOPEN_SOURCE
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| 139 | # undef _XOPEN_SOURCE
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| 140 | #endif
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| 141 | ])dnl
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| 142 | 
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| 143 |   AC_REQUIRE([AC_CHECK_INCLUDES_DEFAULT])dnl
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| 144 |   _AC_CHECK_HEADER_ONCE([wchar.h])
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| 145 |   _AC_CHECK_HEADER_ONCE([minix/config.h])
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| 146 | 
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| 147 | dnl Defining __EXTENSIONS__ may break the system headers on some systems.
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| 148 | dnl (FIXME: Which ones?)
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| 149 |   AC_CACHE_CHECK([whether it is safe to define __EXTENSIONS__],
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| 150 |     [ac_cv_safe_to_define___extensions__],
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| 151 |     [AC_COMPILE_IFELSE(
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| 152 |        [AC_LANG_PROGRAM([[
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| 153 | #         define __EXTENSIONS__ 1
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| 154 |           ]AC_INCLUDES_DEFAULT])],
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| 155 |        [ac_cv_safe_to_define___extensions__=yes],
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| 156 |        [ac_cv_safe_to_define___extensions__=no])])
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| 157 | 
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| 158 | dnl HP-UX 11.11 defines mbstate_t only if _XOPEN_SOURCE is defined to
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| 159 | dnl 500, regardless of whether compiling with -Ae or -D_HPUX_SOURCE=1.
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| 160 | dnl But defining _XOPEN_SOURCE may turn *off* extensions on platforms
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| 161 | dnl not covered by turn-on-extensions macros (notably Dragonfly, Free,
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| 162 | dnl and OpenBSD, which don't have any equivalent of _NETBSD_SOURCE) so
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| 163 | dnl it should only be defined when necessary.
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| 164 |   AC_CACHE_CHECK([whether _XOPEN_SOURCE should be defined],
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| 165 |     [ac_cv_should_define__xopen_source],
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| 166 |     [ac_cv_should_define__xopen_source=no
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| 167 |     AS_IF([test $ac_cv_header_wchar_h = yes],
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| 168 |       [AC_COMPILE_IFELSE(
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| 169 |         [AC_LANG_PROGRAM([[
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| 170 |           #include <wchar.h>
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| 171 |           mbstate_t x;]])],
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| 172 |         [],
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| 173 |         [AC_COMPILE_IFELSE(
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| 174 |           [AC_LANG_PROGRAM([[
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| 175 |             #define _XOPEN_SOURCE 500
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| 176 |             #include <wchar.h>
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| 177 |             mbstate_t x;]])],
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| 178 |           [ac_cv_should_define__xopen_source=yes])])])])
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| 179 | 
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| 180 |   AC_DEFINE([_ALL_SOURCE])
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| 181 |   AC_DEFINE([_DARWIN_C_SOURCE])
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| 182 |   AC_DEFINE([_GNU_SOURCE])
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| 183 |   AC_DEFINE([_HPUX_ALT_XOPEN_SOCKET_API])
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| 184 |   AC_DEFINE([_NETBSD_SOURCE])
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| 185 |   AC_DEFINE([_OPENBSD_SOURCE])
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| 186 |   AC_DEFINE([_POSIX_PTHREAD_SEMANTICS])
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| 187 |   AC_DEFINE([__STDC_WANT_IEC_60559_ATTRIBS_EXT__])
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| 188 |   AC_DEFINE([__STDC_WANT_IEC_60559_BFP_EXT__])
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| 189 |   AC_DEFINE([__STDC_WANT_IEC_60559_DFP_EXT__])
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| 190 |   AC_DEFINE([__STDC_WANT_IEC_60559_FUNCS_EXT__])
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| 191 |   AC_DEFINE([__STDC_WANT_IEC_60559_TYPES_EXT__])
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| 192 |   AC_DEFINE([__STDC_WANT_LIB_EXT2__])
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| 193 |   AC_DEFINE([__STDC_WANT_MATH_SPEC_FUNCS__])
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| 194 |   AC_DEFINE([_TANDEM_SOURCE])
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| 195 |   AS_IF([test $ac_cv_header_minix_config_h = yes],
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| 196 |     [MINIX=yes
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| 197 |     AC_DEFINE([_MINIX])
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| 198 |     AC_DEFINE([_POSIX_SOURCE])
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| 199 |     AC_DEFINE([_POSIX_1_SOURCE], [2])],
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| 200 |     [MINIX=])
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| 201 |   AS_IF([test $ac_cv_safe_to_define___extensions__ = yes],
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| 202 |     [AC_DEFINE([__EXTENSIONS__])])
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| 203 |   AS_IF([test $ac_cv_should_define__xopen_source = yes],
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| 204 |     [AC_DEFINE([_XOPEN_SOURCE], [500])])
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| 205 | ])# AC_USE_SYSTEM_EXTENSIONS
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| 206 | ])
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| 207 | 
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| 208 | # gl_USE_SYSTEM_EXTENSIONS
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| 209 | # ------------------------
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| 210 | # Enable extensions on systems that normally disable them,
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| 211 | # typically due to standards-conformance issues.
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| 212 | AC_DEFUN_ONCE([gl_USE_SYSTEM_EXTENSIONS],
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| 213 | [
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| 214 |   AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
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| 215 | 
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| 216 |   dnl On OpenBSD 6.8 with GCC, the include files contain a couple of
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| 217 |   dnl definitions that are only activated with an explicit -D_ISOC11_SOURCE.
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| 218 |   dnl That's because this version of GCC (4.2.1) supports the option
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| 219 |   dnl '-std=gnu99' but not the option '-std=gnu11'.
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| 220 |   AC_REQUIRE([AC_CANONICAL_HOST])
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| 221 |   case "$host_os" in
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| 222 |     openbsd*)
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| 223 |       AC_DEFINE([_ISOC11_SOURCE], [1],
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| 224 |         [Define to enable the declarations of ISO C 11 types and functions.])
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| 225 |       ;;
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| 226 |   esac
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| 227 | ])
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