$NetBSD: patch-libstdc++-v3_include_std_mutex,v 1.1 2014/01/25 13:38:48 ryoon Exp $

--- libstdc++-v3/include/std/mutex.orig	2012-07-07 18:35:52.000000000 +0000
+++ libstdc++-v3/include/std/mutex
@@ -789,7 +789,7 @@ _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>