fix steed eating feedback

<Someone> reported that riding a steed into a magic portal can
give "steed is still eating" message, feedback normally used to explain why
you can't go down stairs.  Rather than preventing portals from activating
in that situation, just force the meal to be finished in order to suppress
the message.  Proper fix is probably to prevent all steed movement while
eating, but that would most likely result in no one ever riding again.

doc/fixes34.4

@@ -67,6 +67,7 @@ helmets don't protect against cockatrice eggs thrown straight up
 breaking container contents in a shop didn't always charge for them
 some types of shop theft of a stack of items only charged for a single one
 wizard mode: WIZKIT wish for own quest artifact triggered crash at startup
+avoid "your steed is still eating" message when going through a magic portal
 
 
 Platform- and/or Interface-Specific Fixes

src/dog.c

@@ -1,4 +1,4 @@
-/*	SCCS Id: @(#)dog.c	3.4	2004/06/12	*/
+/*	SCCS Id: @(#)dog.c	3.4	2004/11/26	*/
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /* NetHack may be freely redistributed.  See license for details. */
 
@@ -507,6 +507,19 @@ boolean pets_only;	/* true for ascension or final escape */
 		/* monster won't follow if it hasn't noticed you yet */
 		&& !(mtmp->mstrategy & STRAT_WAITFORU)) {
 		stay_behind = FALSE;
+#ifdef STEED
+		if (mtmp == u.usteed) {
+		    /* make sure steed is eligible to accompany hero;
+		       start by having mintrap() give a chance to escape
+		       trap normally but if that fails, force the untrap
+		       (note: handle traps first because normal escape
+		       has the potential to set monster->meating) */
+		    if (mtmp->mtrapped && mintrap(mtmp))
+			mtmp->mtrapped = 0;		/* escape trap */
+		    mtmp->meating = 0;		/* terminate eating */
+		    mdrop_special_objs(mtmp);	/* drop Amulet */
+		} else
+#endif
 		if (mtmp->mtame && mtmp->meating) {
 			if (canseemon(mtmp))
 			    pline("%s is still eating.", Monnam(mtmp));
@@ -521,9 +534,6 @@ boolean pets_only;	/* true for ascension or final escape */
 			    pline("%s is still trapped.", Monnam(mtmp));
 			stay_behind = TRUE;
 		}
-#ifdef STEED
-		if (mtmp == u.usteed) stay_behind = FALSE;
-#endif
 		if (stay_behind) {
 			if (mtmp->mleashed) {
 				pline("%s leash suddenly comes loose.",
@@ -532,6 +542,14 @@ boolean pets_only;	/* true for ascension or final escape */
 					    : "Its");
 				m_unleash(mtmp, FALSE);
 			}
+#ifdef STEED
+			if (mtmp == u.usteed) {
+			    /* can't happen unless someone makes a change
+			       which scrambles the stay_behind logic above */
+			    impossible("steed left behind?");
+			    dismount_steed(DISMOUNT_GENERIC);
+			}
+#endif
 			continue;
 		}
 		if (mtmp->isshk)