Fix #7188: check the validity of command callback for scripts (#7701)

src/script/api/script_object.hpp

@@ -71,6 +71,16 @@ protected:
 	 */
 	static bool DoCommand(TileIndex tile, uint32 p1, uint32 p2, uint cmd, const char *text = NULL, Script_SuspendCallbackProc *callback = NULL);
 
+	/**
+	 * Store the latest command executed by the script.
+	 */
+	static void SetLastCommand(TileIndex tile, uint32 p1, uint32 p2, uint cmd);
+
+	/**
+	 * Check if it's the latest command executed by the script.
+	 */
+	static bool CheckLastCommand(TileIndex tile, uint32 p1, uint32 p2, uint cmd);
+
 	/**
 	 * Sets the DoCommand costs counter to a value.
 	 */