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1 # serial 9 -*- 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, 2006-2010 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 # This definition of AC_USE_SYSTEM_EXTENSIONS is stolen from CVS
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10 # Autoconf. Perhaps we can remove this once we can assume Autoconf
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11 # 2.62 or later everywhere, but since CVS Autoconf mutates rapidly
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12 # enough in this area it's likely we'll need to redefine
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13 # AC_USE_SYSTEM_EXTENSIONS for quite some time.
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14
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15 # If autoconf reports a warning
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16 # warning: AC_COMPILE_IFELSE was called before AC_USE_SYSTEM_EXTENSIONS
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17 # or warning: AC_RUN_IFELSE was called before AC_USE_SYSTEM_EXTENSIONS
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18 # the fix is
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19 # 1) to ensure that AC_USE_SYSTEM_EXTENSIONS is never directly invoked
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20 # but always AC_REQUIREd,
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21 # 2) to ensure that for each occurrence of
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22 # AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
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23 # or
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24 # AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
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25 # the corresponding gnulib module description has 'extensions' among
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26 # its dependencies. This will ensure that the gl_USE_SYSTEM_EXTENSIONS
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27 # invocation occurs in gl_EARLY, not in gl_INIT.
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28
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29 # AC_USE_SYSTEM_EXTENSIONS
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30 # ------------------------
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31 # Enable extensions on systems that normally disable them,
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32 # typically due to standards-conformance issues.
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33 # Remember that #undef in AH_VERBATIM gets replaced with #define by
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34 # AC_DEFINE. The goal here is to define all known feature-enabling
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35 # macros, then, if reports of conflicts are made, disable macros that
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36 # cause problems on some platforms (such as __EXTENSIONS__).
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37 AC_DEFUN_ONCE([AC_USE_SYSTEM_EXTENSIONS],
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38 [AC_BEFORE([$0], [AC_COMPILE_IFELSE])dnl
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39 AC_BEFORE([$0], [AC_RUN_IFELSE])dnl
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40
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41 AC_REQUIRE([AC_CANONICAL_HOST])
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42
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43 AC_CHECK_HEADER([minix/config.h], [MINIX=yes], [MINIX=])
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44 if test "$MINIX" = yes; then
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45 AC_DEFINE([_POSIX_SOURCE], [1],
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46 [Define to 1 if you need to in order for `stat' and other
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47 things to work.])
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48 AC_DEFINE([_POSIX_1_SOURCE], [2],
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49 [Define to 2 if the system does not provide POSIX.1 features
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50 except with this defined.])
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51 AC_DEFINE([_MINIX], [1],
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52 [Define to 1 if on MINIX.])
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53 fi
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54
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55 dnl HP-UX 11.11 defines mbstate_t only if _XOPEN_SOURCE is defined to 500,
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56 dnl regardless of whether the flags -Ae or _D_HPUX_SOURCE=1 are already
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57 dnl provided.
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58 case "$host_os" in
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59 hpux*)
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60 AC_DEFINE([_XOPEN_SOURCE], [500],
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61 [Define to 500 only on HP-UX.])
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62 ;;
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63 esac
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64
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65 AH_VERBATIM([__EXTENSIONS__],
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66 [/* Enable extensions on AIX 3, Interix. */
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67 #ifndef _ALL_SOURCE
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68 # undef _ALL_SOURCE
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69 #endif
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70 /* Enable GNU extensions on systems that have them. */
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71 #ifndef _GNU_SOURCE
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72 # undef _GNU_SOURCE
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73 #endif
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74 /* Enable threading extensions on Solaris. */
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75 #ifndef _POSIX_PTHREAD_SEMANTICS
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76 # undef _POSIX_PTHREAD_SEMANTICS
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77 #endif
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78 /* Enable extensions on HP NonStop. */
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79 #ifndef _TANDEM_SOURCE
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80 # undef _TANDEM_SOURCE
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81 #endif
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82 /* Enable general extensions on Solaris. */
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83 #ifndef __EXTENSIONS__
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84 # undef __EXTENSIONS__
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85 #endif
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86 ])
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87 AC_CACHE_CHECK([whether it is safe to define __EXTENSIONS__],
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88 [ac_cv_safe_to_define___extensions__],
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89 [AC_COMPILE_IFELSE(
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90 [AC_LANG_PROGRAM([[
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91 # define __EXTENSIONS__ 1
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92 ]AC_INCLUDES_DEFAULT])],
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93 [ac_cv_safe_to_define___extensions__=yes],
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94 [ac_cv_safe_to_define___extensions__=no])])
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95 test $ac_cv_safe_to_define___extensions__ = yes &&
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96 AC_DEFINE([__EXTENSIONS__])
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97 AC_DEFINE([_ALL_SOURCE])
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98 AC_DEFINE([_GNU_SOURCE])
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99 AC_DEFINE([_POSIX_PTHREAD_SEMANTICS])
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100 AC_DEFINE([_TANDEM_SOURCE])
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101 ])# AC_USE_SYSTEM_EXTENSIONS
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102
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103 # gl_USE_SYSTEM_EXTENSIONS
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104 # ------------------------
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105 # Enable extensions on systems that normally disable them,
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106 # typically due to standards-conformance issues.
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107 AC_DEFUN_ONCE([gl_USE_SYSTEM_EXTENSIONS],
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108 [
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109 dnl Require this macro before AC_USE_SYSTEM_EXTENSIONS.
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110 dnl gnulib does not need it. But if it gets required by third-party macros
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111 dnl after AC_USE_SYSTEM_EXTENSIONS is required, autoconf 2.62..2.63 emit a
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112 dnl warning: "AC_COMPILE_IFELSE was called before AC_USE_SYSTEM_EXTENSIONS".
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113 dnl Note: We can do this only for one of the macros AC_AIX, AC_GNU_SOURCE,
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114 dnl AC_MINIX. If people still use AC_AIX or AC_MINIX, they are out of luck.
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115 AC_REQUIRE([AC_GNU_SOURCE])
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116
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117 AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
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118 ])
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