$OpenBSD: patch-src_ptlib_common_sockets_cxx,v 1.1 2017/05/07 20:48:29 espie Exp $
--- src/ptlib/common/sockets.cxx.orig	Fri Apr 28 01:50:17 2017
+++ src/ptlib/common/sockets.cxx	Fri Apr 28 01:50:25 2017
@@ -36,6 +36,7 @@
 #include <ptlib/sockets.h>
 
 #include <ctype.h>
+#include <unistd.h>
 
 #define PTraceModule() "Socket"
 
