Add signedness warning flag and fix fallout
diff --git a/src/hash.c b/src/hash.c
index 1dbee82..d841883 100644
--- a/src/hash.c
+++ b/src/hash.c
@@ -212,7 +212,7 @@
 }
 
 static void
-hash_table_rehash(struct hash_table *ht, int new_size_index)
+hash_table_rehash(struct hash_table *ht, unsigned int new_size_index)
 {
 	struct hash_table old_ht;
 	struct hash_entry *table, *entry;