pkstream/pkstream.c: Allow multiple listening and peer addresses.
When being a TCP server.
* Accept multiple `-b' and `-p' options, and accumulate their values
into string vectors;
* expand the `connwait' addresses into vectors;
* when resolving addresses, accumulate the addresses into the
appropriate result vectors;
* maintain multiple `sel_file' objects waiting for their respective
listening sockets;
* and search the vector of peers when accepting incoming
connections (an empty vector means that all remote addresses are
permitted, so we no longer need to dig into the address structure
here).