'luaH_get' functions return 'TValue'

Instead of receiving a parameter telling them where to put the result
of the query, these functions return the TValue directly. (That is,
they return a structure.)

ldump.c

@@ -132,8 +132,8 @@ static void dumpString (DumpState *D, TString *ts) {
   if (ts == NULL)
     dumpSize(D, 0);
   else {
-    TValue idx;
-    if (luaH_getstr(D->h, ts, &idx) == HOK) {  /* string already saved? */
+    TValue idx = luaH_getstr(D->h, ts);
+    if (!isemptyV(idx)) {  /* string already saved? */
       dumpSize(D, 1);  /* reuse a saved string */
       dumpSize(D, cast_sizet(ivalue(&idx)));  /* index of saved string */
     }