- *
- * - possibly disable undo? Or alternatively mark game states as
- * `cheated', although that's horrid.
- * + OK. Rather than _disabling_ undo, we have a hook callable
- * in the game backend which is called before we do an undo.
- * That hook can talk to the game_ui and set the cheated flag,
- * and then make_move can avoid setting the `won' flag after that.