services: Explicitly mark a qsort() callback funtion cdecl.

programs/services/services.c

@@ -322,7 +322,7 @@ static void scmdatabase_remove_service(struct scmdatabase *db, struct service_en
     service->entry.next = service->entry.prev = NULL;
 }
 
-static int compare_tags(const void *a, const void *b)
+static int __cdecl compare_tags(const void *a, const void *b)
 {
     struct service_entry *service_a = *(struct service_entry **)a;
     struct service_entry *service_b = *(struct service_entry **)b;