1 files changed, 7 insertions, 6 deletions

diff --git a/m4/extensions.m4 b/m4/extensions.m4
index 58bc0beb..e71845f1 100644
--- a/m4/extensions.m4
+++ b/m4/extensions.m4
@@ -1,12 +1,9 @@
 # Enable extensions on systems that normally disable them.
 
 # Copyright (C) 2003 Free Software Foundation, Inc.
-
-# This file is free software, distributed under the terms of the GNU
-# General Public License.  As a special exception to the GNU General
-# Public License, this file may be distributed as part of a program
-# that contains a configuration script generated by Autoconf, under
-# the same distribution terms as the rest of that program.
+# 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.
 
 # gl_USE_SYSTEM_EXTENSIONS
 # ------------------------
@@ -24,6 +21,10 @@ AC_DEFUN([gl_USE_SYSTEM_EXTENSIONS], [
 [/* Enable extensions on Solaris.  */
 #ifndef __EXTENSIONS__
 # undef __EXTENSIONS__
+#endif
+#ifndef _POSIX_PTHREAD_SEMANTICS
+# undef _POSIX_PTHREAD_SEMANTICS
 #endif])
   AC_DEFINE([__EXTENSIONS__])
+  AC_DEFINE([_POSIX_PTHREAD_SEMANTICS])
 ])