4 - make it possible to specify stream's external format and buffer size
5 in OPEN-SOCKET-CLIENT and ACCEPT
6 - add read/write timeouts to sockets
7 - rehaul the error hierarchy and make sure that all UNIX-ERRORs are
8 mapped to some subclass of SOCKET-ERROR
11 - make it possible to re-open sockets
12 - add/fix socket options
15 - add MAKE-SOCKET-PAIR
16 - grovel CMSG_* macros
17 - make it possible to send descriptors/credentials over unix sockets
18 - unlink socket file when closing a passive local socket
19 - implement SCTP sockets