$OpenBSD: patch-portinuse_c,v 1.2 2019/03/11 04:06:37 bket Exp $
Index: portinuse.c
--- portinuse.c.orig
+++ portinuse.c
@@ -18,6 +18,7 @@
 #include <errno.h>
 #include <time.h>
 #include <sys/types.h>
+#include <sys/select.h> /* fd_set */
 #include <sys/socket.h>
 #include <netinet/in.h>
 #include <arpa/inet.h>
