lpd run in a mode where the it listens only to the local unix domain
socket and not to the network. Changes are similar but not identical
to the supplied patches.
Also, change `.Os 4.2' => `.Os 4.4' (this man page is from 4.4 lite), and
for now, refer to the "BSD 4.3 Line printer manual", because that is what
we now have in lpr/SMM.doc (SMM.doc needs updating too).