finish_transfer() so that it only gets output when we're actually going
to rename the file.

(which was also made larger).

so I reversed the return.

wasn't always called before w_fds was used.

return value from setsockopt() with one improvement:  if the
user has used --ipv6 (-6) we don't discard the IPv6 socket.
This should help people using older Linux kernels that don't
implement IPv6 support quite right.

minor format tweaks.

off during the second (retry) phase of the transfer to avoid
making a second backup of a file (which would lose the original).

ensures that the remote client has time to read our error message
while it is trying to write data to us before it gets a socket
error.

don't complain about returning a value from a void function.

- Improved the option-error-reporting to actually get the error back
  to the user (by getting I/O multiplexing started).

  to a dir.  This fixes deletions inside "kept" symlinked dirs.
- Call link_stat() with its new arg (for --keep-dirlinks support).