tin variety followup (trunk only)

src/eat.c

@@ -1008,13 +1008,13 @@ int forcetype;
 		return;
 	} else if (forcetype >= 0 && forcetype < TTSZ-1) {
 		r = forcetype;
-	} else {
+	} else {	/* RANDOM_TIN */
 		r = rn2(TTSZ-1);		/* take your pick */
 		if (r == ROTTEN_TIN && (obj->corpsenm == PM_LIZARD ||
 			 		obj->corpsenm == PM_LICHEN))
 			r = HOMEMADE_TIN;	/* lizards don't rot */
 	}
-	obj->spe = -(r+1);
+	obj->spe = -(r+1);	/* offset by 1 to allow index 0 */
 }
 
 STATIC_OVL int
@@ -1027,7 +1027,7 @@ struct obj *obj;
 		r = ROTTEN_TIN;			/* always rotten if cursed */
 	} else if (obj->spe < 0) {
 		r = -(obj->spe);
-		--r;
+		--r;		/* get rid of the offset */
 	} else 
 		r = rn2(TTSZ-1);
 

src/mkobj.c

@@ -431,7 +431,7 @@ boolean artif;
 		    if (mons[mndx].cnutrit &&
 			    !(mvitals[mndx].mvflags & G_NOCORPSE)) {
 			otmp->corpsenm = mndx;
-			set_tin_variety(otmp, 0);
+			set_tin_variety(otmp, RANDOM_TIN);
 			break;
 		    }
 		}

src/objnam.c

@@ -1802,7 +1802,7 @@ boolean from_user;
 #endif
 		ispoisoned = isgreased = eroded = eroded2 = erodeproof =
 		halfeaten = islit = unlabeled = ishistoric = isdiluted = 0;
-	tvariety = -1;
+	tvariety = RANDOM_TIN;
 	mntmp = NON_PM;
 #define UNDEFINED 0
 #define EMPTY 1