Install xbase in OpenBSD afterwards

So you created a headless OpenBSD box only to install php-gd or some other packages that still relies on an X library.  You need to install xbase.  To do so:

ftp http://mirrors.nycbug.org/pub/OpenBSD/5.6/amd64/xbase56.tgz

tar -C / -xzphf xbase56.tgz