+ return a->sub_type < b->sub_type ? -1 : a->sub_type > b->sub_type;
+}
+
+/* Attaches a struct mxd_var with the specific member values to
+ V. */
+static void
+attach_mxd_aux (struct variable *v, int var_type, int sub_type)
+{
+ struct mxd_var *mv;
+
+ assert (v->aux == NULL);
+ mv = xmalloc (sizeof *mv);
+ mv->var_type = var_type;
+ mv->sub_type = sub_type;
+ var_attach_aux (v, mv, var_dtor_free);