Using a cursed tin whistle in a vault summons the guard

...since guards respond to shrill whistles.
Based on a patch by Leon Arnott.

doc/fixes36.1

@@ -405,6 +405,7 @@ fix the 'A' command to have the 'D' command's fix for C331-1 (quirk for
 	response, to operate on applicable all items, there would still be a
 	followup menu asking to choose specific items)
 eating 1 tin from stack of N (for N >= 2) on shop's floor forced hero to buy 2
+using a cursed whistle in a vault will summon the guard immediately
 
 
 Fixes to Post-3.6.0 Problems that Were Exposed Via git Repository

include/extern.h

@@ -2510,6 +2510,7 @@ E int FDECL(hide_privileges, (BOOLEAN_P));
 E void FDECL(newegd, (struct monst *));
 E void FDECL(free_egd, (struct monst *));
 E boolean FDECL(grddead, (struct monst *));
+E void NDECL(vault_summon_gd);
 E char FDECL(vault_occupied, (char *));
 E void NDECL(invault);
 E int FDECL(gd_move, (struct monst *));

include/hack.h

@@ -34,6 +34,9 @@ enum encumbrance_types {
 /* weight increment of heavy iron ball */
 #define IRON_BALL_W_INCR 160
 
+/* number of turns it takes for vault guard to show up */
+#define VAULT_GUARD_TIME 30
+
 /* hunger states - see hu_stat in eat.c */
 enum hunger_state_types {
     SATIATED = 0,

src/apply.c

@@ -445,6 +445,8 @@ struct obj *obj;
     } else {
         You(whistle_str, obj->cursed ? "shrill" : "high");
         wake_nearby();
+        if (obj->cursed)
+            vault_summon_gd();
     }
 }
 

src/vault.c

@@ -191,6 +191,13 @@ findgd()
     return (struct monst *) 0;
 }
 
+void
+vault_summon_gd()
+{
+    if (vault_occupied(u.urooms) && !findgd())
+        u.uinvault = (VAULT_GUARD_TIME - 1);
+}
+
 char
 vault_occupied(array)
 char *array;
@@ -221,7 +228,8 @@ invault()
     vaultroom -= ROOMOFFSET;
 
     guard = findgd();
-    if (++u.uinvault % 30 == 0 && !guard) { /* if time ok and no guard now. */
+    if (++u.uinvault % VAULT_GUARD_TIME == 0 && !guard) {
+        /* if time ok and no guard now. */
         char buf[BUFSZ];
         register int x, y, dd, gx, gy;
         int lx = 0, ly = 0;