> socket-flock.patch
>
> use advisory locks to check if the unix socket can be deleted.
> A running postmaster keeps a lock on that file. A starting
> postmaster exits if the file exists and is locked, otherwise
> it deletes the sockets and proceeds.
> This avoid the need to remove manually the file after a postmaster
> or system crash.
> I don't know if flock is available on any system. If not we could
> define a HAVE_FLOCK set by configure.