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

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

Change all kernel C-type macros into static inline functions.

The current kernel C-type macros might obscurely hide the fact that
the input argument might be used multiple times.

This breaks code like:
isalpha(*ptr++)

Use static inline functions instead of macros to fix this.

Reviewed by: kib @
Differential Revision: https://reviews.freebsd.org/D19694
MFC after: 1 week
Sponsored by: Mellanox Technologies

sys: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 3-Clause license.

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.

Renumber copyright clause 4

Renumber cluase 4 to 3, per what everybody else did when BSD granted
them permission to remove clause 3. My insistance on keeping the same
numbering for legal reasons is too pedantic, so give up on that point.

Submitted by: Jan Schaumann <jschauma@stevens.edu>
Pull Request: https://github.com/freebsd/freebsd/pull/96

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.

Remove advertising clause from University of California Regent's license,
per letter dated July 22, 1999.

Approved by: core

Resolve conflicts arising from the ACPI CA 20021118 import.

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.

Move isfoo() and friends to the newly created sys/ctype.h.

Urged by: bde