Remove $FreeBSD$: one-line sh pattern

Remove /^\s*#[#!]?\s*\$FreeBSD\$.*$\n/

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.

The last big commit: let usr.sbin/ use WARNS=6 by default.

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

o Implement net.inet.tcp.drop sysctl and userland part, tcpdrop(8)
utility:

The tcpdrop command drops the TCP connection specified by the
local address laddr, port lport and the foreign address faddr,
port fport.

Obtained from: OpenBSD
Reviewed by: rwatson (locking), ru (man page), -current
MFC after: 1 month