diff -uNr openvpn-2.4.7/src/openvpn/console_builtin.c openvpn-2.4.7.mod/src/openvpn/console_builtin.c
--- openvpn-2.4.7/src/openvpn/console_builtin.c	2019-02-20 14:28:20.000000000 +0200
+++ openvpn-2.4.7.mod/src/openvpn/console_builtin.c	2019-09-18 14:32:21.891795281 +0300
@@ -40,6 +40,8 @@
 #include "buffer.h"
 #include "misc.h"
 
+#include <unistd.h>
+
 #ifdef _WIN32
 
 #include "win32.h"