fixed bug introduced during OOM fixup causing problems with default

* SAX2.c: fixed bug introduced during OOM fixup causing problems
  with default namespace when a named prefix with the same href
  was present (reported on the mailing list by Karl Eichwalder.
* xmlstring.c: modified xmlCheckUTF8 with suggested code from
  Julius Mittenzwei.
* dict.c: added a typecast to try to avoid problem reported by
  Pascal Rodes.
diff --git a/dict.c b/dict.c
index 2ffd6a5..56c5dfb 100644
--- a/dict.c
+++ b/dict.c
@@ -708,7 +708,7 @@
 	return(-1);
     pool = dict->strings;
     while (pool != NULL) {
-        if ((str >= pool->array) && (str <= pool->free))
+        if ((str >= &pool->array[0]) && (str <= pool->free))
 	    return(1);
 	pool = pool->next;
     }