Make mergesort setup() static
diff --git a/src/merge.c b/src/merge.c
index 470352a..c82594c 100644
--- a/src/merge.c
+++ b/src/merge.c
@@ -255,7 +255,7 @@ COPY: b = t;
* when THRESHOLD/2 pairs compare with same sense. (Only used when NATURAL
* is defined. Otherwise simple pairwise merging is used.)
*/
-void
+static void
setup(u_char *list1, u_char *list2, size_t n, size_t size,
int (*cmp)(const void *, const void *))
{