Save current menu to temp variable when entering options from in-game

This is to pre-emptively prevent piling up stack frames for what I'll be
adding next, which is pressing Esc in the options menu in-game
automatically moving you back to MAPMODE.

desktop_version/src/Game.h

@@ -216,6 +216,7 @@ public:
     std::vector<MenuOption> menuoptions;
     int currentmenuoption ;
     enum Menu::MenuName currentmenuname;
+    enum Menu::MenuName kludge_ingametemp;
     int current_credits_list_index;
     int menuxoff, menuyoff;
     std::vector<MenuStackFrame> menustack;