Remove $FreeBSD$: two-line .h pattern

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

Move unsigned limits to a separate table/recognizer and display them
using the appropriate (unsigned) format specification. This prevents
integer overflow when ULLONG_MAX and (on some architectures) ULONG_MAX
are used to initialize an intmax_t and then displayed as the signed
value -1. (A different approach was suggested in the bug report,
which I did not use.) If other limits are defined to be unsigned,
they could be moved here.

PR: 164049
Reported by: Marcus Reid

Add an -a flag to getconf.

When -a is specified, the name and value of all system or path
configuration values is reported to standard output.

Reviewed by: kib (earlier version)
MFC after: 1 week
Sponsored by: Chelsio Communications
Differential Revision: https://reviews.freebsd.org/D12373

Revert local changes to find_progenv accidentally committed in r318436

MFC after: 2 weeks
MFC with: r318436
Sponsored by: Dell EMC Isilon

usr.bin/getconf: add some initial tests

Items tested via this commit are:
- Some basic POSIX constants.
- Some valid programming environments with -v.
- Some invalid programming environments via -v.

NOTE: this test makes assumptions about ILP32/LP32 vs LP64 that are
currently not true on all architectures to avoid hardcoding some
architectures in the tests. I'm working on improving getconf(1) to be
more sane about handling ILP32/LP32 vs LP64. Future commits are coming
soon to address this.

MFC after: 2 weeks
Tested with: amd64, i386
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.

Remove unnecessary compatibility macro. (We were only printing, not parsing,
intmax_t.)

Add new 1003.1-2001/TC1/D6 parameters. (On final recirculation ballot now,
so this should be officially TC1 before the New Year.)

Add TrustedBSD pathconf parameters.

Add compilation support for -stable (to be merged momentarily).

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.)

Hello, getconf. This is a slight reinvention of the
wheel^H^H^H^H^HPOSIX.2 and X/Open utility, and rather
more complicated than necessary.