$OpenBSD: patch-mono_utils_networking-posix_c,v 1.2 2018/01/02 13:19:10 robert Exp $
Index: mono/utils/networking-posix.c
--- mono/utils/networking-posix.c.orig
+++ mono/utils/networking-posix.c
@@ -18,6 +18,7 @@
 #include <sys/ioctl.h>
 #endif
 #ifdef HAVE_NET_IF_H
+#include <sys/socket.h>
 #include <net/if.h>
 #endif
 #ifdef HAVE_UNISTD_H
