Fix #7050: Missing guard around network chat message function for compiling with networking disabled. (#7058)

src/window.cpp

@@ -3100,11 +3100,13 @@ void UpdateWindows()
 
 	CallWindowRealtimeTickEvent(delta_ms);
 
+#ifdef ENABLE_NETWORKING
 	static GUITimer network_message_timer = GUITimer(1);
 	if (network_message_timer.Elapsed(delta_ms)) {
 		network_message_timer.SetInterval(1000);
 		NetworkChatMessageLoop();
 	}
+#endif
 
 	Window *w;