replace fuzzer state magic numbers

include/flag.h

@@ -224,6 +224,12 @@ struct accessibility_data {
             a11y.mon_notices_blocked = 0;                           \
         } } while(0)
 
+enum debug_fuzzer_states {
+    fuzzer_off,
+    fuzzer_impossible_panic,
+    fuzzer_impossible_continue
+};
+
 /*
  * Stuff that really isn't option or platform related and does not
  * get saved and restored.  They are set and cleared during the game

src/end.c

@@ -77,7 +77,7 @@ done1(int sig_unused UNUSED)
 #ifndef NO_SIGNAL
     (void) signal(SIGINT, SIG_IGN);
 #endif
-    iflags.debug_fuzzer = FALSE;
+    iflags.debug_fuzzer = fuzzer_off;
     if (flags.ignintr) {
 #ifndef NO_SIGNAL
         (void) signal(SIGINT, (SIG_RET_TYPE) done1);

src/pline.c

@@ -587,7 +587,7 @@ impossible(const char *s, ...)
     va_end(the_args);
     pbuf[BUFSZ - 1] = '\0'; /* sanity */
     paniclog("impossible", pbuf);
-    if (iflags.debug_fuzzer == 1)
+    if (iflags.debug_fuzzer == fuzzer_impossible_panic)
         panic("%s", pbuf);
 
     gp.pline_flags = URGENT_MESSAGE;

src/wizcmds.c

@@ -551,8 +551,14 @@ wiz_fuzzer(void)
         pline("The fuzz tester will make NetHack execute random keypresses.");
         There("is no conventional way out of this mode.");
     }
-    if (paranoid_query(TRUE, "Do you want to start fuzz testing?"))
+    if (paranoid_query(TRUE, "Do you want to start fuzz testing?")) {
-        iflags.debug_fuzzer = TRUE; /* Thoth, take the reins */
+        /* Thoth, take the reins */
+        if (y_n("Do you want to call panic() after impossible()?") == 'n') {
+            iflags.debug_fuzzer = fuzzer_impossible_continue;
+        } else {
+            iflags.debug_fuzzer = fuzzer_impossible_panic;
+        }
+    }
     return ECMD_OK;
 }