sys: Remove $FreeBSD$: two-line .h pattern

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

SPDX: Consider code from Carnegie-Mellon University.

Interesting cases, most likely from CMU Mach sources.

ddb: finish converting boolean values.

The replacement started at r283088 was necessarily incomplete without
replacing boolean_t with bool. This also involved cleaning some type
mismatches and ansifying old C function declarations.

Pointed out by: bde
Discussed with: bde, ian, jhb

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

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

Start each of the license/copyright comments with /*-

Remove __P.

$Id$ -> $FreeBSD$

Back out part 1 of the MCFH that changed $Id$ to $FreeBSD$. We are not
ready for it yet.

Make the long-awaited change from $Id$ to $FreeBSD$

This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.

Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.

Reduced and cleaned up #includes.

Completed function declarations and/or added prototypes.
Removed `extern' from prototypes.
Sorted prototypes.
Uniformized idempotency ifdefs.

Remove trailing whitespace.

Make all headers idempotent. All incorrect common data moved out of header
files and into a related source file.

Removed all patch kit headers, sccsid and rcsid strings, put $Id$ in, some
minor cleanup. Added $Id$ to files that did not have any version info, etc

Initial import, 0.1 + pk 0.2.4-B1