Merge GDB 7.5.1

gdb/gnulib/m4/extensions.m4

-# serial 9  -*- Autoconf -*-
-# Enable extensions on systems that normally disable them.
-
-# Copyright (C) 2003, 2006-2011 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.
-
-# If autoconf reports a warning
-#     warning: AC_COMPILE_IFELSE was called before AC_USE_SYSTEM_EXTENSIONS
-# or  warning: AC_RUN_IFELSE was called before AC_USE_SYSTEM_EXTENSIONS
-# the fix is
-#   1) to ensure that AC_USE_SYSTEM_EXTENSIONS is never directly invoked
-#      but always AC_REQUIREd,
-#   2) to ensure that for each occurrence of
-#        AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
-#      or
-#        AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
-#      the corresponding gnulib module description has 'extensions' among
-#      its dependencies. This will ensure that the gl_USE_SYSTEM_EXTENSIONS
-#      invocation occurs in gl_EARLY, not in gl_INIT.
-
-# AC_USE_SYSTEM_EXTENSIONS
-# ------------------------
-# Enable extensions on systems that normally disable them,
-# typically due to standards-conformance issues.
-# Remember that #undef in AH_VERBATIM gets replaced with #define by
-# AC_DEFINE.  The goal here is to define all known feature-enabling
-# macros, then, if reports of conflicts are made, disable macros that
-# 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
-       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 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([_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])
-])