Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Port ppp(8) to utmpx.

A nice thing about utmpx is that it makes it very easy to log sessions
that don't use TTYs. This is because the file is not indexed by TTY
slots anymore.

Silence from: brian

Fix the NOSUID build: make sure we have the kldload(2) prototype.

Make -DNOSUID (or -DPPP_NOSUID) possible to build ppp without SUID
capabilities.

setproctitle() doesn't need to be called with root privs, so move
it from id.c into defs.c

Call MkSockNode() as uid 0

Forgotten by: julian

Fix ``set proctitle'' by using setproctitle().

Use modfind() to check if a kld is already loaded.

Submitted mostly by: green

Don't (unnecessarily) parse wtmp, force ID0logout() to DTRT instead.

Do a kldload() if we get ENXIO trying to open /dev/tun0

Originally submitted by: green

$Id$ -> $FreeBSD$

o If there's a session leader left running for a descriptor
that we're now closing, manually HUP that session leader
so that the tty is fully released.
o Always restart our carrier detect timer in the receiving
process if it was running in the sending process (as we
now *always* pass the descriptor).
o Tweak argv when we go into pause() mode to keep our session
so that ps can see what's going on (without checking for a
`pause' state in `ps -l').

o Don't forget to close our transfer socket if we cannot
generate the data to transfer.
o Transfer uucp lock ownership for the transferred device.
o Don't assume we know the correct values of dev_is_modem and
mbits after the transfer.

MFMP: Make ppp multilink capable.
See the file README.changes, and re-read the man page.

MFMP: Allow 8 character login names.
Do the login()/logwtmp()/logout() as id 0.

Write to the routing socket as uid 0. It's not good enough
to just open it as uid 0 under OpenBSD.

Add (BSD) copyright headers.

Introduce ID0 logging.
Stay as the invoking uid as much as possible.
Execution as a normal user is still forbidden for now,
so these changes are pretty ineffective.
The next commit will implement the modifications suggested
on -hackers a number of days ago.