Merge GDB 7.5.1

gdb/gnulib/import/m4/extensions.m4

-# serial 9  -*- Autoconf -*-
+# serial 12  -*- Autoconf -*-
 # Enable extensions on systems that normally disable them.
 
-# Copyright (C) 2003, 2006-2011 Free Software Foundation, Inc.
+# Copyright (C) 2003, 2006-2012 Free Software Foundation, Inc.
 # This file is free software; the Free Software Foundation
 # gives unlimited permission to copy and/or distribute it,
 # with or without modifications, as long as this notice is preserved.
 
 # This definition of AC_USE_SYSTEM_EXTENSIONS is stolen from CVS
 # Autoconf.  Perhaps we can remove this once we can assume Autoconf
 # 2.62 or later everywhere, but since CVS Autoconf mutates rapidly
 # enough in this area it's likely we'll need to redefine
 # AC_USE_SYSTEM_EXTENSIONS for quite some time.
 
@@ skipping 21 matching lines @@
 # cause problems on some platforms (such as __EXTENSIONS__).
 AC_DEFUN_ONCE([AC_USE_SYSTEM_EXTENSIONS],
 [AC_BEFORE([$0], [AC_COMPILE_IFELSE])dnl
 AC_BEFORE([$0], [AC_RUN_IFELSE])dnl
 
   AC_REQUIRE([AC_CANONICAL_HOST])
 
   AC_CHECK_HEADER([minix/config.h], [MINIX=yes], [MINIX=])
   if test "$MINIX" = yes; then
     AC_DEFINE([_POSIX_SOURCE], [1],
-      [Define to 1 if you need to in order for `stat' and other
+      [Define to 1 if you need to in order for 'stat' and other
        things to work.])
     AC_DEFINE([_POSIX_1_SOURCE], [2],
       [Define to 2 if the system does not provide POSIX.1 features
        except with this defined.])
     AC_DEFINE([_MINIX], [1],
       [Define to 1 if on MINIX.])
   fi
 
   dnl HP-UX 11.11 defines mbstate_t only if _XOPEN_SOURCE is defined to 500,
   dnl regardless of whether the flags -Ae or _D_HPUX_SOURCE=1 are already
   dnl provided.
   case "$host_os" in
     hpux*)
       AC_DEFINE([_XOPEN_SOURCE], [500],
         [Define to 500 only on HP-UX.])
       ;;
   esac
 
   AH_VERBATIM([__EXTENSIONS__],
 [/* Enable extensions on AIX 3, Interix.  */
 #ifndef _ALL_SOURCE
 # undef _ALL_SOURCE
 #endif
+/* Enable general extensions on Mac OS X.  */
+#ifndef _DARWIN_C_SOURCE
+# undef _DARWIN_C_SOURCE
+#endif
 /* Enable GNU extensions on systems that have them.  */
 #ifndef _GNU_SOURCE
 # undef _GNU_SOURCE
 #endif
 /* Enable threading extensions on Solaris.  */
 #ifndef _POSIX_PTHREAD_SEMANTICS
 # undef _POSIX_PTHREAD_SEMANTICS
 #endif
 /* Enable extensions on HP NonStop.  */
 #ifndef _TANDEM_SOURCE
 # undef _TANDEM_SOURCE
 #endif
 /* Enable general extensions on Solaris.  */
 #ifndef __EXTENSIONS__
 # undef __EXTENSIONS__
 #endif
 ])
   AC_CACHE_CHECK([whether it is safe to define __EXTENSIONS__],
     [ac_cv_safe_to_define___extensions__],
     [AC_COMPILE_IFELSE(
        [AC_LANG_PROGRAM([[
 #         define __EXTENSIONS__ 1
           ]AC_INCLUDES_DEFAULT])],
        [ac_cv_safe_to_define___extensions__=yes],
        [ac_cv_safe_to_define___extensions__=no])])
   test $ac_cv_safe_to_define___extensions__ = yes &&
     AC_DEFINE([__EXTENSIONS__])
   AC_DEFINE([_ALL_SOURCE])
+  AC_DEFINE([_DARWIN_C_SOURCE])
   AC_DEFINE([_GNU_SOURCE])
   AC_DEFINE([_POSIX_PTHREAD_SEMANTICS])
   AC_DEFINE([_TANDEM_SOURCE])
 ])# AC_USE_SYSTEM_EXTENSIONS
 
 # gl_USE_SYSTEM_EXTENSIONS
 # ------------------------
 # Enable extensions on systems that normally disable them,
 # typically due to standards-conformance issues.
 AC_DEFUN_ONCE([gl_USE_SYSTEM_EXTENSIONS],
 [
   dnl Require this macro before AC_USE_SYSTEM_EXTENSIONS.
   dnl gnulib does not need it. But if it gets required by third-party macros
   dnl after AC_USE_SYSTEM_EXTENSIONS is required, autoconf 2.62..2.63 emit a
   dnl warning: "AC_COMPILE_IFELSE was called before AC_USE_SYSTEM_EXTENSIONS".
   dnl Note: We can do this only for one of the macros AC_AIX, AC_GNU_SOURCE,
   dnl AC_MINIX. If people still use AC_AIX or AC_MINIX, they are out of luck.
   AC_REQUIRE([AC_GNU_SOURCE])
 
   AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
 ])