Dehardcode number of glass gems

src/mon.c

@@ -572,7 +572,8 @@ make_corpse(struct monst *mtmp, unsigned int corpseflags)
     case PM_GLASS_GOLEM:
         num = d(2, 4); /* very low chance of creating all glass gems */
         while (num--)
-            obj = mksobj_at((LAST_GEM + rnd(9)), x, y, TRUE, FALSE);
+            obj = mksobj_at((LAST_GEM + rnd(NUM_GLASS_GEMS)),
+                            x, y, TRUE, FALSE);
         free_mgivenname(mtmp);
         break;
     case PM_CLAY_GOLEM:

src/mthrowu.c

@@ -556,7 +556,7 @@ m_throw(
                 nomul(0);
 
             if (singleobj->oclass == GEM_CLASS
-                && singleobj->otyp <= LAST_GEM + 9 /* 9 glass colors */
+                && singleobj->otyp <= LAST_GEM + NUM_GLASS_GEMS
                 && is_unicorn(g.youmonst.data)) {
                 if (singleobj->otyp > LAST_GEM) {
                     You("catch the %s.", xname(singleobj));

src/objnam.c

@@ -3956,7 +3956,7 @@ readobjnam_postparse2(struct _readobjnam_data *d)
             s += 9;
         if (!strcmpi(s, "glass")) { /* choose random color */
             /* 9 different kinds */
-            d->typ = LAST_GEM + rnd(9);
+            d->typ = LAST_GEM + rnd(NUM_GLASS_GEMS);
             if (objects[d->typ].oc_class == GEM_CLASS)
                 return 2; /*goto typfnd;*/
             else