Remove $FreeBSD$: two-line .h pattern

Remove /^\s*\*\n \*\s+\$FreeBSD\$$\n/

dhclient: build with WARNS=6

- add static in a number of places
- initialize __progname rather than rely on magical extern values
- use nitems() instead of manually spelling it out
- unshadow 'idi'
- teach 'error' that it is '__dead2'
- add missing 'break'

dhclient: raise WARNS to 4

Mostly const-correctness fixes. There were also some variable-shadowing,
unused variable, and a couple of sockaddr type-correctness changes. I also had
trouble with cast-align warnings. I was able to prove that one of them was a
false positive. But ultimately I had to disable the warning program-wide to
deal with the others.

Reviewed by: cem
MFC after: 3 weeks
Sponsored by: Spectra Logic Corp
Differential Revision: https://reviews.freebsd.org/D14460

dhclient: add support for interface-mtu (26)

Make dhclient set interface MTU if it was provided.

This version implements MTU setting in dhclient itself before it runs
dhclient-script.

PR: 206721
Submitted by: novel@
Reported by: Jarrod Petz <jlpetz at gmail.com>
Reviewed by: cem, allanjude
Differential Revision: https://reviews.freebsd.org/D5675

MFp4 @229479:

- Add new request (IMSG_SEND_PACKET) that will be handled by privileged process.
- Add $FreeBSD$.

Reviewed by: brooks
Sponsored by: The FreeBSD Foundation

A new jail(8) with a configuration file, to replace the work currently done
by /etc/rc.d/jail.

Create the altix project branch. The altix project will add support
for the SGI Altix 350 to FreeBSD/ia64. The hardware used for porting
is a two-module system, consisting of a base compute module and a
CPU expansion module. SGI's NUMAFlex architecture can be an excellent
platform to test CPU affinity and NUMA-aware features in FreeBSD.

- Import the HEAD csup code which is the basis for the cvsmode work.

Import the OpenBSD dhclient as shipped with OpenBSD-3.7 (the tag
OPENBSD_3_7).