Ensure running __gc of userdata created in __gc at state close.

src/lj_state.c

@@ -242,12 +242,17 @@ LUA_API void lua_close(lua_State *L)
   G2J(g)->state = LJ_TRACE_IDLE;
   lj_dispatch_update(g);
 #endif
-  do {
+  for (;;) {
     hook_enter(g);
     L->status = 0;
     L->cframe = NULL;
     L->base = L->top = tvref(L->stack) + 1;
-  } while (lj_vm_cpcall(L, NULL, NULL, cpfinalize) != 0);
+    if (lj_vm_cpcall(L, NULL, NULL, cpfinalize) == 0) {
+      lj_gc_separateudata(g, 1);  /* Separate udata again. */
+      if (gcref(g->gc.mmudata) == NULL)  /* Until nothing is left to do. */
+	break;
+    }
+  }
   close_state(L);
 }