$OpenBSD: patch-src_ptlib_unix_tlib_cxx,v 1.4 2017/05/07 20:48:29 espie Exp $
--- src/ptlib/unix/tlib.cxx.orig	Fri Apr 28 01:45:13 2017
+++ src/ptlib/unix/tlib.cxx	Fri Apr 28 01:45:25 2017
@@ -63,6 +63,7 @@
 #endif // P_VXWORKS
 #include <signal.h>
 #include <sys/wait.h>
+#include <unistd.h>
 #include <errno.h>
 
 #if defined(P_LINUX) || defined(P_GNU_HURD)
