listen queues for AF_UNIX sockets

[Ben <bench@xxxxxxxxxxxxxx>]

A long time ago there was a thread on this list where it was pointed out
that listen queues are not built for AF_UNIX sockets. I never saw any
follow-up about this being fixed, and it's not clear from the comments in
af_unix.c for recent versions of the 2.2 kernel that the problem has been
delt with... was it? Does listen() now do what you would expect it to for
unix domain sockets?

I ask because the symptoms I'm having in my program indicate that unix
domain sockets still might not have queues.