# serial 5  -*- Autoconf -*-
# Enable extensions on systems that normally disable them.

# Copyright (C) 2003, 2006, 2008 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
# 2.61 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.

# AC_USE_SYSTEM_EXTENSIONS
# ------------------------
# Enable extensions on systems that normally disable them,
# typically due to standards-conformance issues.
m4_ifdef([AC_USE_SYSTEM_EXTENSIONS], [], [
AC_DEFUN([AC_USE_SYSTEM_EXTENSIONS],
[
  AC_BEFORE([$0], [AC_COMPILE_IFELSE])
  AC_BEFORE([$0], [AC_RUN_IFELSE])

  AC_REQUIRE([AC_GNU_SOURCE])
  AC_REQUIRE([AC_AIX])
  AC_REQUIRE([AC_MINIX])

  AH_VERBATIM([__EXTENSIONS__],
[/* Enable extensions on Solaris.  */
#ifndef __EXTENSIONS__
# undef __EXTENSIONS__
#endif
#ifndef _POSIX_PTHREAD_SEMANTICS
# undef _POSIX_PTHREAD_SEMANTICS
#endif
#ifndef _TANDEM_SOURCE
# undef _TANDEM_SOURCE
#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([_POSIX_PTHREAD_SEMANTICS])
  AC_DEFINE([_TANDEM_SOURCE])
])])

# gl_USE_SYSTEM_EXTENSIONS
# ------------------------
# Enable extensions on systems that normally disable them,
# typically due to standards-conformance issues.
AC_DEFUN([gl_USE_SYSTEM_EXTENSIONS],
  [AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])])
