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-rw-r--r--m4/ChangeLog7
-rw-r--r--m4/extensions.m413
2 files changed, 18 insertions, 2 deletions
diff --git a/m4/ChangeLog b/m4/ChangeLog
index d7bcb1d77..fc323c47c 100644
--- a/m4/ChangeLog
+++ b/m4/ChangeLog
@@ -1,3 +1,10 @@
+2006-02-05 Paul Eggert <eggert@cs.ucla.edu>
+
+ * extensions.m4 (gl_USE_SYSTEM_EXTENSIONS): Don't #define
+ __EXTENSIONS__ if this causes compilation to fail. Problem
+ reported by Nelson H. F. Beebe with Solaris 10 and Sun C 5.7
+ c89 -D_XOPEN_SOURCE -D_XOPEN_SOURCE_EXTENDED.
+
2006-01-26 Paul Eggert <eggert@cs.ucla.edu>
* stdbool.m4 (AC_HEADER_STDBOOL): Sync from gnulib.
diff --git a/m4/extensions.m4 b/m4/extensions.m4
index e71845f1d..5f22d4276 100644
--- a/m4/extensions.m4
+++ b/m4/extensions.m4
@@ -1,6 +1,6 @@
# Enable extensions on systems that normally disable them.
-# Copyright (C) 2003 Free Software Foundation, Inc.
+# Copyright (C) 2003, 2006 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.
@@ -25,6 +25,15 @@ AC_DEFUN([gl_USE_SYSTEM_EXTENSIONS], [
#ifndef _POSIX_PTHREAD_SEMANTICS
# undef _POSIX_PTHREAD_SEMANTICS
#endif])
- AC_DEFINE([__EXTENSIONS__])
+ 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])
])