Remove $FreeBSD$: two-line .h pattern

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

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.

Discussed with: pfg
MFC After: 3 days
Sponsored by: Netflix

various: general adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

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.

No functional change intended.

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.

Don't use sys/nfs/rpcv2.h - it is part of the old kernel RPC implementation
and will be removed.

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

Fix some bugs and general brain damage in mounttab:
- Declare mtabhead as an extern in mounttab.h and define it only in
mounttab.c.
- Remove shared global `verbose' and instead pass it as a parameter.
- Remove the `mtabp' argument to read_mtab(). It served no purpose
whatsoever, although read_mtab() did use it as a temporary local
variable.
- Don't check for impossible conditions when parsing mounttab, and
do detect zero-length fields.
- Correctly test for strtoul() failures - just testing ERANGE is wrong.
- Include a field name in syslog errors, and avoid passing NULL to
a syslog %s field.
- Don't test if arrays are NULL.
- If there are duplicates when writing out mounttab, keep the last
entry instead of the first, as it will have a later timestamp.
- Fix a few formatting issues.

Update rpc.umntall and umount to match the mounttab interface changes.

Add rpc.umntall utility, to be used by startup and shutdown scripts
to replace (broken) umntall signal code previously in mountd.

Submitted by: Martin Blapp <mb@imp.ch>