diff -r 000000000000 -r 6474c204b198 xpcom/glue/unused.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/xpcom/glue/unused.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,28 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=8 et :
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_unused_h
+#define mozilla_unused_h
+
+#include "nscore.h"
+
+namespace mozilla {
+
+//
+// Suppress GCC warnings about unused return values with
+//   unused << SomeFuncDeclaredWarnUnusedReturnValue();
+//
+struct NS_COM_GLUE unused_t { };
+
+extern const unused_t NS_COM_GLUE unused;
+
+template<typename T>
+inline void operator<<(const unused_t& /*unused*/, const T& /*unused*/) { }
+
+}
+
+#endif // mozilla_unused_h