Cleanup: the `mouse_priorities' field in the back end has been a

more general-purpose flags word for some time now. Rename it to
`flags'.

[originally from svn r6414]

dominosa.c

@@ -1778,5 +1778,5 @@ const struct game thegame = {
     TRUE, FALSE, game_print_size, game_print,
     game_wants_statusbar,
     FALSE, game_timing_state,
-    0,				       /* mouse_priorities */
+    0,				       /* flags */
 };