Remove $FreeBSD$: one-line sh pattern

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

getconf: use nitems(..) to compute NWORDS instead of hardcoding
the equivalent macro

MFC after: 1 month
Sponsored by: Dell EMC Isilon

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.

Warns fixes. Mainly unused headers/params/vars removal, but also
some malloc cleanup.

Completely revamp the way getconf(1) works, for better adherence to the
intent of the Standard.

- Make getconf able to distinguish between configuration variables which
are entirely unknown and those which are merely not defined in the
compilation environment. The latter now get a more appropriate
"undefined\n" result rather than a diagnostic. This may not be
exactly right, but it's closer to the intent of the Standard than
the previous behavior.

- Support ``programming environments'' by validating that the environment
requested with the `-v' flag is the one-and-only execution environment.
(If more environments are supported for some platforms in the future,
multiple getconf(1) executables will be required, but a simple edit in
progenv.gperf will enable automatic support for it.) Document POSIX
standard programming environments.

- Add all of the 1003.1-2001 configuration variables. FreeBSD does not
support all of these (including some that are mandatory); getconf will
later be fixed to break the world should a required variable not be
defined.

As a result of all these changes, gperf is no longer adequate. Keep the
overall format and names of the files for now, to preserve revision history.
Use an awk script to process the .gperf files into C source, which does a
few things that gperf, as a more general tool, cannot do. The keyword
recognition function is no longer a perfect hash function.

This may obviate the need for gperf in the source tree.

- Add a small compile-time regression test to break the build if any of the
.gperf files declare conflicting token sets. (gperf itself would have done
this for the simple case of duplicate tokens in the same input file.)

Make obrien happy. Add a bad awk script which emulates as much of
gperf's behavior as we ever actually needed here. This generates
a much-less-efficient keyword recognizer, but it's not like that matters
in this application. Makefile changes coming once this passes the world
test.