Add new "tty" request, which allows TIOCGETA, TIOCGPGRP, TIOCGWINSZ,
TIOCSBRK, TIOCCDTR, TIOCSETA, TIOCSETAW, and TIOCSETAF on tty
vnodes. This helps programs which call tcsetattr(), tcgetattr(), or
readpassphrase(). Especially the latter - tame's goal is to satisfy
the libc requirements of security-sensitive programs.
Remove TIOCSETAF from the basic "ioctl" request, because it is a "set"
option. "ioctl" is slowly turning into a "request information, cannot
set options" package.
Split the "cmsg" request into "sendfd" and "recvfd". Non-SCM_RIGHTS
messages are currently flowing through freely and we'll need to think
about that. This split lets us more strictly describe what our many
fd-passing programs will do.