tree: enable cmp_cache_name_compare() to be used elsewhere

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/tree.c b/tree.c
index e76517f..a524798 100644
--- a/tree.c
+++ b/tree.c
@@ -144,7 +144,7 @@ int read_tree_recursive(struct repository *r,
 	return ret;
 }
 
-static int cmp_cache_name_compare(const void *a_, const void *b_)
+int cmp_cache_name_compare(const void *a_, const void *b_)
 {
 	const struct cache_entry *ce1, *ce2;