wand/spell/breath killer reason

Extend "killed by the touch of death inflicted by <monster>" to buzz().
"Killed by a bolt of cold" becomes "killed by a bolt of cold zapped by
<monster>" or "killed by a blast of cold" becomes "killed by a blast
of cold exhaled by <monster>" and so forth.

More work than expected; the zap code isn't passed enough context.

BZ_M_WAND() was producing the wrong value for wands zapped by monsters.

include/decl.h

@@ -793,6 +793,9 @@ struct instance_globals_b {
     /* pickup.c */
     boolean bucx_filter;
 
+    /* zap.c */
+    struct monst *buzzer; /* zapper/caster/breather who initiates buzz() */
+
     boolean havestate;
     unsigned long magic; /* validate that structure layout is preserved */
 };

include/extern.h

@@ -1322,6 +1322,7 @@ extern boolean usmellmon(struct permonst *);
 
 extern int castmu(struct monst *, struct attack *, boolean, boolean);
 extern void touch_of_death(struct monst *);
+extern char *death_inflicted_by(char *, const char *, struct monst *);
 extern int buzzmu(struct monst *, struct attack *);
 
 /* ### mdlib.c ### */

include/hack.h

@@ -677,12 +677,12 @@ enum getobj_callback_returns {
 #define BZ_U_SPELL(bztyp) (10 + (bztyp))
 /* hero breathing as a monster */
 #define BZ_U_BREATH(bztyp) (20 + (bztyp))
+/* monster shooting a wand */
+#define BZ_M_WAND(bztyp) (-0 - (bztyp))
 /* monster casting a spell */
 #define BZ_M_SPELL(bztyp) (-10 - (bztyp))
 /* monster breathing */
 #define BZ_M_BREATH(bztyp) (-20 - (bztyp))
-/* monster shooting a wand */
-#define BZ_M_WAND(bztyp) (-30 - (bztyp))
 
 /*
  * option setting restrictions