Add override and final placeolders for old GCC compatibility

libresapi/src/api/RsControlModule.h

@@ -1,6 +1,7 @@
 #pragma once
 
 #include <util/rsthreads.h>
+#include <util/cxx11retrocompat.h>
 #include <retroshare/rsnotify.h>
 #include "api/ResourceRouter.h"
 

libretroshare/src/libretroshare.pro

@@ -532,7 +532,8 @@ HEADERS +=	util/folderiterator.h \
 			util/rsrecogn.h \
 			util/rsscopetimer.h \
             util/stacktrace.h \
-            util/rsdeprecate.h
+            util/rsdeprecate.h \
+            util/cxx11retrocompat.h
 
 SOURCES +=	ft/ftchunkmap.cc \
 			ft/ftcontroller.cc \

libretroshare/src/util/cxx11retrocompat.h

@@ -0,0 +1,25 @@
+#pragma once
+/*
+ * RetroShare
+ * Copyright (C) 2017  Gioacchino Mazzurco <gio@eigenlab.org>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifdef __GNUC__
+#	if __GNUC__*100 + __GNUC_MINOR__ < 40700
+#		define override
+#		define final
+#	endif //GCC version
+#endif //defined GNUC