jail for linux_base?

[David Syphers]

The ports@ archives show several other people have asked this question 
recently, but I haven't seen any threads where anyone _answers_ it. I'm 
trying to install linux_base from the ports (well, I'm actually trying to 
install apsfilter), and I get the message:

-----
You need to create the null device in your jailed Linux environment. Run this
outside the jail, then press enter:

mkdir -m 0755 -p <Jail root dir>/dev
rm -f <Jail root dir>/compat/linux/dev/null
mknod <Jail root dir>/compat/linux/dev/null c 2 2
chmod 666 <Jail root dir>/compat/linux/dev/null
-----

What does this mean and how do I deal with it? This is apparently a fairly 
recent change to linux_base, as I've never had to do anything like this 
before. I have no jails on my system. I'm running a Feb. 10 -CURRENT.

-David

-- 
Department of Physics
The University of Washington, Seattle