ignore "maybe uninitialized" warning in game lua kernel.

This breaks compilation for gcc 4.9.2 with -O2, with an apparently
spurious warning.

src/scripting/game_lua_kernel.cpp

@@ -128,6 +128,11 @@ class CVideo;
 #include "scripting/debug_lua.hpp"
 #endif
 
+// Suppress uninitialized variables warnings, because of boost::optional constructors in this file which apparently confuses gcc
+#if defined(__GNUC__) && !defined(__clang__) // we shouldn't need this for clang, but for gcc and tdm-gcc we probably do
+#pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
+#endif
+
 static lg::log_domain log_scripting_lua("scripting/lua");
 #define LOG_LUA LOG_STREAM(info, log_scripting_lua)
 #define WRN_LUA LOG_STREAM(warn, log_scripting_lua)