api checks to ensure that thread is OK when using lua_call/lua_pcall

lapi.c

@@ -1,5 +1,5 @@
 /*
-** $Id: lapi.c,v 2.132 2010/07/02 17:35:06 roberto Exp roberto $
+** $Id: lapi.c,v 2.133 2010/07/25 15:18:19 roberto Exp roberto $
 ** Lua API
 ** See Copyright Notice in lua.h
 */
@@ -799,6 +799,7 @@ LUA_API void lua_callk (lua_State *L, int nargs, int nresults, int ctx,
   api_check(L, k == NULL || !isLua(L->ci),
     "cannot use continuations inside hooks");
   api_checknelems(L, nargs+1);
+  api_check(L, L->status == LUA_OK, "cannot do calls on non-normal thread");
   checkresults(L, nargs, nresults);
   func = L->top - (nargs+1);
   if (k != NULL && L->nny == 0) {  /* need to prepare continuation? */
@@ -839,6 +840,7 @@ LUA_API int lua_pcallk (lua_State *L, int nargs, int nresults, int errfunc,
   api_check(L, k == NULL || !isLua(L->ci),
     "cannot use continuations inside hooks");
   api_checknelems(L, nargs+1);
+  api_check(L, L->status == LUA_OK, "cannot do calls on non-normal thread");
   checkresults(L, nargs, nresults);
   if (errfunc == 0)
     func = 0;