refine the issue #349 fix

Accept or ignore the in-hell-only and non-in-hell-only flags on
a monster type by monster type basis instead of all or nothing
for a given mkclass() call.  Prevents demon summoning outside of
Gehennom from bringing in only succubi and incubi 10 times out
of 11 and mixture of demons the other time.

src/makemon.c

@@ -1,4 +1,4 @@
-/* NetHack 3.6	makemon.c	$NHDT-Date: 1590613502 2020/05/27 21:05:02 $  $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.170 $ */
+/* NetHack 3.6	makemon.c	$NHDT-Date: 1590621476 2020/05/27 23:17:56 $  $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.171 $ */
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /*-Copyright (c) Robert Patrick Rankin, 2012. */
 /* NetHack may be freely redistributed.  See license for details. */
@@ -1663,7 +1663,7 @@ aligntyp atyp;
 {
     register int first, last, num = 0;
     int k, nums[SPECIAL_PM + 1]; /* +1: insurance for final return value */
-    int maxmlev, gmask;
+    int maxmlev, gmask, gehennom = Inhell != 0;
 
     (void) memset((genericptr_t) nums, 0, sizeof nums);
     maxmlev = level_difficulty() >> 1;
@@ -1685,23 +1685,23 @@ aligntyp atyp;
         return (struct permonst *) 0;
     }
 
-    gmask = (G_NOGEN | G_UNIQ);
-    /* traditionally mkclass() ignored hell-only and never-in-hell;
-       now we usually honor those but not all the time, mostly so that
-       the majority of major demons aren't constrained to Gehennom;
-       arch- and master liches are always so constrained (for creation;
-       lesser liches might grow up into them elsewhere) */
-    if (rn2(9) || class == S_LICH)
-        gmask |= (Inhell ? G_NOHELL : G_HELL);
-    gmask &= ~spc;
-    gmask |= (spc & G_IGNORE);
-
     /*  Assumption #2:  monsters of a given class are presented in ascending
      *                  order of strength.
      */
     for (last = first; last < SPECIAL_PM && mons[last].mlet == class; last++) {
         if (atyp != A_NONE && sgn(mons[last].maligntyp) != sgn(atyp))
             continue;
+        /* traditionally mkclass() ignored hell-only and never-in-hell;
+           now we usually honor those but not all the time, mostly so that
+           the majority of major demons aren't constrained to Gehennom;
+           arch- and master liches are always so constrained (for creation;
+           lesser liches might grow up into them elsewhere) */
+        gmask = (G_NOGEN | G_UNIQ);
+        if (rn2(9) || class == S_LICH)
+            gmask |= (gehennom ? G_NOHELL : G_HELL);
+        gmask &= ~spc;
+        gmask |= (spc & G_IGNORE);
+
         if (mk_gen_ok(last, G_GONE, gmask)) {
             /* consider it; don't reject a toostrong() monster if we
                don't have anything yet (num==0) or if it is the same
@@ -1757,6 +1757,8 @@ int class;
         return NON_PM;
 
     gmask = (G_NOGEN | G_UNIQ);
+    /* mkclass() does this on a per monster type basis, but doing that here
+       would make the two loops inconsistent with each other for non L */
     if (rn2(9) || class == S_LICH)
         gmask |= (Inhell ? G_NOHELL : G_HELL);