re PR libstdc++/50982 (AIX libstdc++ GTHREADS incompatibility)

	PR libstdc++/50982
	* include/std/mutex (__once_proxy): Use void parameter list to
	work on implicit extern "C" systems.

From-SVN: r181072

libstdc++-v3/ChangeLog

+2011-11-07  Jonathan Wakely  <jwakely.gcc@gmail.com>
+
+	PR libstdc++/50982
+	* include/std/mutex (__once_proxy): Use void parameter list to
+	work on implicit extern "C" systems.
+
 2011-11-07  Xinliang David Li  <davidxl@google.com>
 
 	* include/backward/hashtable.h: Make __stl_prime_list

libstdc++-v3/include/std/mutex

@@ -796,7 +796,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
   __get_once_mutex();
 #endif
 
-  extern "C" void __once_proxy();
+  extern "C" void __once_proxy(void);
 
   /// call_once
   template<typename _Callable, typename... _Args>