New type 'TStatus' for thread status/error codes

lgc.c

@@ -953,7 +953,7 @@ static void GCTM (lua_State *L) {
   setgcovalue(L, &v, udata2finalize(g));
   tm = luaT_gettmbyobj(L, &v, TM_GC);
   if (!notm(tm)) {  /* is there a finalizer? */
-    int status;
+    TStatus status;
     lu_byte oldah = L->allowhook;
     lu_byte oldgcstp  = g->gcstp;
     g->gcstp |= GCSTPGC;  /* avoid GC steps */