ghash: Call g_error if hash table grows too large

Gracefully handle the case when too many items (billions) are added to a
hash table.

glib/ghash.c

@@ -289,6 +289,9 @@ static const gint prime_mod [] =
 static void
 g_hash_table_set_shift (GHashTable *hash_table, gint shift)
 {
+  if (shift > 31)
+    g_error ("adding more entries to hash table would overflow");
+
   hash_table->size = 1 << shift;
   hash_table->mod  = prime_mod [shift];