Squashed 'third_party/protobuf/' content from commit e35e248
Change-Id: I6cbe123d09fe50fdcad0e51466665daeee7433c7
git-subtree-dir: third_party/protobuf
git-subtree-split: e35e24800fb8d694bdeea5fd63dc7d1b14d68723
diff --git a/m4/ac_system_extensions.m4 b/m4/ac_system_extensions.m4
new file mode 100644
index 0000000..1ca2eeb
--- /dev/null
+++ b/m4/ac_system_extensions.m4
@@ -0,0 +1,37 @@
+dnl Provide AC_USE_SYSTEM_EXTENSIONS for old autoconf machines.
+AC_DEFUN([ACX_USE_SYSTEM_EXTENSIONS],[
+ ifdef([AC_USE_SYSTEM_EXTENSIONS],[
+ 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])
+ ])
+])