follow-up

adjust the mon_offmap(mon) macro to test any of the bits that
constitute being off the map, while ignoring some of the other bits
that do not.

include/monst.h

@@ -257,7 +257,10 @@ struct monst {
 
 #define mon_perma_blind(mon) (!mon->mcansee && !mon->mblinded)
 
-#define mon_offmap(mon) ((mon)->mstate != MON_FLOOR)
+#define MON_OFF_MAP_BITS (MON_OFFMAP | MON_DETACH | MON_LIMBO | MON_MIGRATING \
+                          | MON_ENDGAME_FREE | MON_ENDGAME_MIGR | MON_BUBBLEMOVE)
+
+#define mon_offmap(mon) (((mon)->mstate & (MON_OFF_MAP_BITS)) != 0)
 
 /* Get the maximum difficulty monsters that can currently be generated,
    given the current level difficulty and the hero's level. */

src/steed.c

@@ -935,11 +935,10 @@ place_monster(struct monst *mon, coordxy x, coordxy y)
        bits that may be set. We'll probably make MON_FLOOR an
        actual bit one day */
 
-    mon->mstate &= ~(MON_OFFMAP | MON_DETACH | MON_LIMBO | MON_MIGRATING
-		     | MON_ENDGAME_FREE | MON_ENDGAME_MIGR);
+    mon->mstate &= ~(MON_OFF_MAP_BITS);
 
     /* We don't mess with these bits above:
-       MON_BUBBLEMOVE | MON_OBLITERATE | MON_STILL_ARRIVING | MON_PARKED
+       MON_OBLITERATE | MON_STILL_ARRIVING | MON_PARKED
      */
 }