Moved -u (udp) to -c (connectionless). Connectionless is depreciated
and undocumented.
Added tests for set{,e}{u,g}id to configure. Use existance of
setuid/setgid to enable feature. Use seteuid/setegid only if
they exist.
Fixed minor minor leak of username/groupname if specificied
more than once. (This should actually be an error)