offshoot of #H1820 - priests/minions vs opposite alignment (trunk only)

In #H1820, <email deleted> reported that helms
of opposite alignment didn't work for monsters.  There's never been
any attempt to implement that, and it wasn't omitted by accident, so
I wouldn't classify it as a bug.  But it does seem buggy that temple
priests and minions of <deity> would be willing to put such helms on
and risk changing allegiance to another deity.  This lets other types
of monsters still wear helms of opposite alignment as ordinary head
protection, but the explicity aligned creatures won't do so anymore.

doc/fixes35.0

@@ -314,6 +314,7 @@ attacking via applied polearm never scuffed engraving underneath hero
 auto-wielding a polearm took no time if ESC was used to cancel target choice
 applying a bullwhip while at very edge of map could target beyond edge,
 	potentially leading to a panic or crash
+prevent temple priests and minions from wearing helms of opposite alignment
 
 
 Platform- and/or Interface-Specific Fixes

src/worn.c

@@ -1,4 +1,4 @@
-/*	SCCS Id: @(#)worn.c	3.5	2008/09/03	*/
+/*	SCCS Id: @(#)worn.c	3.5	2009/02/28	*/
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /* NetHack may be freely redistributed.  See license for details. */
 
@@ -503,6 +503,11 @@ boolean racialexception;
 		    break;
 		case W_ARMH:
 		    if (!is_helmet(obj)) continue;
+		    /* changing alignment is not implemented for monsters;
+		       priests and minions could change alignment but wouldn't
+		       want to, so they reject helms of opposite alignment */
+		    if (obj->otyp == HELM_OF_OPPOSITE_ALIGNMENT &&
+			    (mon->ispriest || mon->isminion)) continue;
 		    /* (flimsy exception matches polyself handling) */
 		    if (has_horns(mon->data) && !is_flimsy(obj)) continue;
 		    break;