Macro for picking random entry from array

src/mondata.c

@@ -1546,7 +1546,7 @@ get_atkdam_type(int adtyp)
         static const int rnd_breath_typ[] = {
             AD_MAGM, AD_FIRE, AD_COLD, AD_SLEE,
             AD_DISN, AD_ELEC, AD_DRST, AD_ACID };
-        return rnd_breath_typ[rn2(SIZE(rnd_breath_typ))];
+        return ROLL_FROM(rnd_breath_typ);
     }
     return adtyp;
 }