mind flayer vs ghost (trunk only)

There's newsgroup discussion about a mind flayer sucking the brains
of a ghost, plus speculation that the fix for C343-121 has already taken
care of it.  I agree with them that ghost's brains are too insubstantial
to be hit by brainsuck damage from mind flayers' tentacles.  C343-121 is
vague enough to cover this; the corresponding fixes entry was more specific
and is augmented here.

doc/fixes35.0

@@ -88,6 +88,7 @@ prevent polymorphing into "new man" at low level from magnifying HP and Pw
 losing a level while polymorphed affects hero's current monster HP as well as
 	underlying normal HP
 mind flayer brain eating is subject to certain fatal targets and to cannibalism
+mind flayer can't eat brains of ghost or shade
 corpses of unique monsters in bones behaved incorrectly if revived or eaten
 fix pluralization for "this tin smells like mother-in-laws" when hallucinating
 try harder to keep pluralization straight when user assigns an already plural

src/eat.c

@@ -468,7 +468,12 @@ int *dmg_p;	/* for dishing out extra damage in lieu of Int loss */
     boolean give_nutrit = FALSE;
     int result = MM_HIT, xtra_dmg = rnd(10);
 
-    if (magr == &youmonst) {
+    if (noncorporeal(pd)) {
+	if (visflag)
+	    pline("%s brain is unharmed.",
+		  (mdef == &youmonst) ? "Your" : s_suffix(mon_nam(mdef)));
+	return MM_MISS;	/* side-effects can't occur */
+    } else if (magr == &youmonst) {
 	You("eat %s brain!", s_suffix(mon_nam(mdef)));
     } else if (mdef == &youmonst) {
 	Your("brain is eaten!");

src/mhitu.c

@@ -1073,8 +1073,15 @@ dopois:
 		if (Half_physical_damage) dmg = (dmg+1) / 2;
 		mdamageu(mtmp, dmg);
 
-		if (!uarmh || uarmh->otyp != DUNCE_CAP)
+		if (!uarmh || uarmh->otyp != DUNCE_CAP) {
-		    (void) eat_brains(mtmp, &youmonst, TRUE, (int *)0);
+		    /* eat_brains() will miss if target is mindless (won't
+		       happen here; hero is considered to retain his mind
+		       regardless of current shape) or is noncorporeal
+		       (can't happen here; no one can poly into a ghost
+		       or shade) so this check for missing is academic */
+		    if (eat_brains(mtmp, &youmonst, TRUE, (int *)0) == MM_MISS)
+			break;
+		}
 		/* adjattrib gives dunce cap message when appropriate */
 		(void) adjattrib(A_INT, -rnd(2), FALSE);
 		forget_levels(25);	/* lose memory of 25% of levels */