use ngx_int_t in ngx_sort() callback
diff --git a/src/core/ngx_string.c b/src/core/ngx_string.c
index 0ac0017..01d792f 100644
--- a/src/core/ngx_string.c
+++ b/src/core/ngx_string.c
@@ -1430,7 +1430,7 @@
 
 void
 ngx_sort(void *base, size_t n, size_t size,
-    int (*cmp)(const void *, const void *))
+    ngx_int_t (*cmp)(const void *, const void *))
 {
     u_char  *p1, *p2, *p;