will facilitate implementing the RTPCD prototcol in a multi-threaded server.
We need to be able to create an RTCPD  callback listener socket within the run
function of a thread and then accept the initial connection made by RTCPD (as
opposed to the 4 or more connections we will later receive from the TAPE IO and
DISK IO threads).  This accept must have a timeout otherwise we could easily
have a server that simply locks up if RTCPD never connects back.