- convert unix <-> dos style pathnames for AF_UNIX, currently the
  pathnames given in a `struct sockaddr_un' *must* be DOS style
  DONE.

- write recvmsg(), sendmsg() emulation
  DONE.

- make strerror(), perror() work for the new socket related error codes
  DONE.

- find a way to make fstat() on socket descriptors return S_IFSOCK
  for the file mode

- make select() work for execptional conditions (must be done in the
  kernel)
