blindness vs vault guards

I implemented this before seeing <Someone>'s forwarded report.
It makes guards come to vaults when you can't see them, but does
have one odd side-effect:  if the vault has boulders in the way
then you might not be able to follow the guard out.  (Usually you
can alternately search and step in order to successfully follow
him out when unable to see.)

doc/fixes34.1

@@ -192,6 +192,7 @@ grammar tid: "The looking glass miss the <monster>."
 fix wishing for "looking glass" and "<color> glass"
 Archeologists suffer same alignment penalty for statue destruction by
 	stone_to_flesh as they do by other means of statue destruction
+being unable to see a vault guard doesn't prevent him from arriving
 
 
 Platform- and/or Interface-Specific Fixes

src/vault.c

@@ -1,4 +1,4 @@
-/*	SCCS Id: @(#)vault.c	3.4	2002/04/18	*/
+/*	SCCS Id: @(#)vault.c	3.4	2002/08/06	*/
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /* NetHack may be freely redistributed.  See license for details. */
 
@@ -234,14 +234,12 @@ fnd:
 	EGD(guard)->vroom = vaultroom;
 	EGD(guard)->warncnt = 0;
 
-	if(!cansee(guard->mx, guard->my)) {
-		mongone(guard);
-		return;
-	}
-
 	reset_faint();			/* if fainted - wake up */
-	pline("Suddenly one of the Vault's %s enters!",
-	      makeplural(g_monnam(guard)));
+	if (canspotmon(guard))
+	    pline("Suddenly one of the Vault's %s enters!",
+		  makeplural(g_monnam(guard)));
+	else
+	    pline("Someone else has entered the Vault.");
 	newsym(guard->mx,guard->my);
 	if ((youmonst.m_ap_type == M_AP_OBJECT &&
 		youmonst.mappearance == GOLD_PIECE) || u.uundetected) {
@@ -736,7 +734,7 @@ cleanup:
 		restfakecorr(grd);
 		if(!semi_dead && (in_fcorridor(grd, u.ux, u.uy) ||
 				     cansee(x, y))) {
-		    if (!disappear_msg_seen)
+		    if (!disappear_msg_seen && canspotmon(grd))
 			pline("Suddenly, the %s disappears.", g_monnam(grd));
 		    return(1);
 		}