using new 'lua_newuserdatauv' instead of 'lua_newuserdata'

liolib.c

@@ -1,5 +1,5 @@
 /*
-** $Id: liolib.c,v 2.153 2017/11/16 13:19:06 roberto Exp roberto $
+** $Id: liolib.c,v 2.154 2017/11/16 16:28:36 roberto Exp roberto $
 ** Standard I/O (and system) library
 ** See Copyright Notice in lua.h
 */
@@ -186,7 +186,7 @@ static FILE *tofile (lua_State *L) {
 ** handle is in a consistent state.
 */
 static LStream *newprefile (lua_State *L) {
-  LStream *p = (LStream *)lua_newuserdata(L, sizeof(LStream));
+  LStream *p = (LStream *)lua_newuserdatauv(L, sizeof(LStream), 0);
   p->closef = NULL;  /* mark file handle as 'closed' */
   luaL_setmetatable(L, LUA_FILEHANDLE);
   return p;