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

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

spdx: initial adoption of licensing ID tags.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.

Initially, only tag files that use BSD 4-Clause "Original" license.

RelNotes: yes
Differential Revision: https://reviews.freebsd.org/D13133

Remove pc98 support completely.
I thank all developers and contributors for pc98.

Relnotes: yes

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.

/* -> /*- for copyright notices, minor format tweaks as necessary

GC various bits and pieces of USERCONFIG from all over the place.

Supported PC-98.

Change #ifdef KERNEL to #ifdef _KERNEL in the public headers. "KERNEL"
is an application space macro and the applications are supposed to be free
to use it as they please (but cannot). This is consistant with the other
BSD's who made this change quite some time ago. More commits to come.

s/LOGIGAL/LOGICAL/

This represents essentially a complete rewrite of the ISA PnP code. The
new system is integrated with the ISA bus code more cleanly and allows
the future addition of more enumerators such as PnPBIOS and ACPI.

This commit also enables the new pcm driver since it is somewhat tied to
the new PnP code.