revived unicorn horns (trunk only)

     Back in Nov'04, <Someone> pointed out that even with only 5%
chance for dropping a horn upon the death of a unicorn which has been
revived from corpse, it's still possible to produce a nearly unlimited
number of them for polypile fodder.  This bumps the chance for a horn up
to 50%, but flags the horn as coming from a revived corpse and makes such
horns be treated by polymoprh as if they're non-magic (which practically
guarantees that they'll poly into mundane tools instead of magic ones).

doc/fixes35.0

@@ -206,6 +206,7 @@ charge for kicked shop-owned food if it gets used up taming a monster
 give better feedback when thrown shop-owned food gets used up taming a monster
 effect of negative AC on damage received was calculated differently than
 	normal when deciding whether hero poly'd into pudding would split
+unicorn horn produced by revived monster will polymorph as if non-magic
 
 
 Platform- and/or Interface-Specific Fixes

include/obj.h

@@ -1,4 +1,4 @@
-/*	SCCS Id: @(#)obj.h	3.5	2007/02/17	*/
+/*	SCCS Id: @(#)obj.h	3.5	2007/03/30	*/
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /* NetHack may be freely redistributed.  See license for details. */
 
@@ -85,6 +85,7 @@ struct obj {
 	Bitfield(oerodeproof,1); /* erodeproof weapon/armor */
 	Bitfield(olocked,1);	/* object is locked */
 	Bitfield(obroken,1);	/* lock has been broken */
+#define degraded_horn obroken	/* unicorn horn will poly to non-magic */
 	Bitfield(otrapped,1);	/* container is trapped */
 				/* or accidental tripped rolling boulder trap */
 #define opoisoned otrapped	/* object (weapon) is coated with poison */

src/mon.c

@@ -1,4 +1,4 @@
-/*	SCCS Id: @(#)mon.c	3.5	2007/02/08	*/
+/*	SCCS Id: @(#)mon.c	3.5	2007/03/30	*/
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /* NetHack may be freely redistributed.  See license for details. */
 
@@ -191,12 +191,14 @@ unsigned corpseflags;
 	    case PM_WHITE_UNICORN:
 	    case PM_GRAY_UNICORN:
 	    case PM_BLACK_UNICORN:
-		if (mtmp->mrevived && rn2(20)) {
-			if (canseemon(mtmp))
-			   pline("%s recently regrown horn crumbles to dust.",
-				s_suffix(Monnam(mtmp)));
-		} else
-			(void) mksobj_at(UNICORN_HORN, x, y, TRUE, FALSE);
+		if (mtmp->mrevived && rn2(2)) {
+		    if (canseemon(mtmp))
+			pline("%s recently regrown horn crumbles to dust.",
+			      s_suffix(Monnam(mtmp)));
+		} else {
+		    obj = mksobj_at(UNICORN_HORN, x, y, TRUE, FALSE);
+		    if (obj && mtmp->mrevived) obj->degraded_horn = 1;
+		}
 		goto default_1;
 	    case PM_LONG_WORM:
 		(void) mksobj_at(WORM_TOOTH, x, y, TRUE, FALSE);

src/zap.c

@@ -1,4 +1,4 @@
-/*	SCCS Id: @(#)zap.c	3.5	2007/02/17	*/
+/*	SCCS Id: @(#)zap.c	3.5	2007/03/30	*/
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /* NetHack may be freely redistributed.  See license for details. */
 
@@ -1283,14 +1283,17 @@ poly_obj(obj, id)
 	    change_luck(-1);	/* Sokoban guilt */
 	if (id == STRANGE_OBJECT) { /* preserve symbol */
 	    int try_limit = 3;
+	    unsigned magic_obj = objects[obj->otyp].oc_magic;
+
+	    if (obj->otyp == UNICORN_HORN && obj->degraded_horn) magic_obj = 0;
 	    /* Try up to 3 times to make the magic-or-not status of
 	       the new item be the same as it was for the old one. */
 	    otmp = (struct obj *)0;
 	    do {
 		if (otmp) delobj(otmp);
 		otmp = mkobj(obj->oclass, FALSE);
 	    } while (--try_limit > 0 &&
-		  objects[obj->otyp].oc_magic != objects[otmp->otyp].oc_magic);
+			objects[otmp->otyp].oc_magic != magic_obj);
 	} else {
 	    /* literally replace obj with this new thing */
 	    otmp = mksobj(id, FALSE, FALSE);