$OpenBSD: patch-src_openvpn_syshead_h,v 1.3 2017/02/16 21:16:55 kurt Exp $
--- src/openvpn/syshead.h.orig	Wed Feb 15 11:34:39 2017
+++ src/openvpn/syshead.h	Wed Feb 15 11:35:49 2017
@@ -288,6 +288,10 @@
 #include <netinet/ip.h>
 #endif
 
+#ifdef HAVE_NETINET_TCP_H
+#include <netinet/tcp.h>
+#endif
+
 #ifdef HAVE_NET_IF_TUN_H
 #include <net/if_tun.h>
 #endif
