hlink: Fix function pointer cast in qsort()

Replace unsafe generic function pointer cast with proper type cast for
qsort() comparison function. This fixes a potential type mismatch
warning without changing the behavior.

Signed-off-by: Charalampos Mitrodimas <charmitro@posteo.net>

Author: charmitro

hlink.c

@@ -117,7 +117,7 @@ static void match_gnums(int32 *ndx_list, int ndx_count)
 	struct ht_int32_node *node = NULL;
 	int32 gnum, gnum_next;
 
-	qsort(ndx_list, ndx_count, sizeof ndx_list[0], (int (*)()) hlink_compare_gnum);
+	qsort(ndx_list, ndx_count, sizeof ndx_list[0], (int (*)(const void*, const void*))hlink_compare_gnum);
 
 	for (from = 0; from < ndx_count; from++) {
 		file = hlink_flist->sorted[ndx_list[from]];