[PATCH:shmfd 2/2] Use /var/tmp instead of /run/shm on non-linux OS'es

[Mark Kettenis]

> Date: Fri, 8 Nov 2013 09:42:57 -0500
> From: "Jasper St. Pierre" <jstpierre at mecheye.net>
> 
> We want to make sure we don't write files to disk. /tmp on some systems is
> backed by a disk, not tmpfs.

And /run doesn't exist on many Linux systems.  In the end this is just
some test code, so I guess it doesn't matter all that much.