sys: Automated cleanup of cdefs and other formatting

Apply the following automated changes to try to eliminate
no-longer-needed sys/cdefs.h includes as well as now-empty
blank lines in a row.

Remove /^#if.*\n#endif.*\n#include\s+<sys/cdefs.h>.*\n/
Remove /\n+#include\s+<sys/cdefs.h>.*\n+#if.*\n#endif.*\n+/
Remove /\n+#if.*\n#endif.*\n+/
Remove /^#if.*\n#endif.*\n/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/types.h>/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/param.h>/
Remove /\n+#include\s+<sys/cdefs.h>\n#include\s+<sys/capsicum.h>/

Sponsored by: Netflix

sys: Remove $FreeBSD$: one-line .c pattern

Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\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spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD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

geom(4): Fix some of the "set but not used" warnings

The few I've left in place look like potential bugs.

Sponsored By: EPSRC

GEOM: Reduce unnecessary log interleaving with sbufs

Similar to what was done for device_printfs in r347229.

Convert g_print_bio() to a thin shim around g_format_bio(), which acts on an
sbuf; documented in g_bio.9.

Reviewed by: markj
Discussed with: rlibby
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D21165

sys/geom: 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.

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

- Check flag with the bitwise operator, not the logical operator.

Submitted by: arundel
MFC after: 1 week

- Remove assertion of topology lock remaining from 7.x gvinum. It is not needed,
as the renaming only changes internal gvinum names and will not alter the geom
topology.
- The topology lock was not held when calling g_wither_geom after renaming.

Import the gvinum work that have been done during and after Summer of Code 2007.
The work have been under testing and fixing since then, and it is mature enough
to be put into HEAD for further testing.

A lot have changed in this time, and here are the most important:
- Gvinum now uses one single workerthread instead of one thread for each
volume and each plex. The reason for this is that the previous scheme was
very complex, and was the cause of many of the bugs discovered in gvinum.
Instead, gvinum now uses one worker thread with an event queue, quite
similar to what used in gmirror.
- The rebuild/grow/initialize/parity check routines no longer runs in
separate threads, but are run as regular I/O requests with special flags.
This made it easier to support mounted growing and parity rebuild.
- Support for growing striped and raid5-plexes, meaning that one can extend the
volumes for these plex types in addition to the concat type. Also works while
the volume is mounted.
- Implementation of many of the missing commands from the old vinum:
attach/detach, start (was partially implemented), stop (was partially
implemented), concat, mirror, stripe, raid5 (shortcuts for creating volumes
with one plex of these organizations).
- The parity check and rebuild no longer goes between userland/kernel, meaning
that the gvinum command will not stay and wait forever for the rebuild to
finish. You can instead watch the status with the list command.
- Many problems with gvinum have been reported since 5.x, and some has been hard
to fix due to the complicated architecture. Hopefully, it should be more
stable and better handle edge cases that previously made gvinum crash.
- Failed drives no longer disappears entirely, but now leave behind a dummy
drive that makes sure the original state is not forgotten in case the system
is rebooted between drive failures/swaps.
- Update manpage to reflect new commands and extend it with some examples.

Sponsored by: Google Summer of Code 2007
Mentored by: le
Tested by: Rick C. Petty <rick-freebsd2008 -at- kiwi-computer.com>

- Fix a potential NULL pointer reference. Note that this cannot happen in
practice, but it is a good programming practice nontheless and it allows the
kernel to not depend on userland correctness.

Found with: Coverity Prevent(tm)
CID: 655-659, 664-667

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

- When renaming a drive, also set the drive name in the gvinum header.

PR: kern/125632
Approved by: pjd (mentor)
MFC after: 3 days

Whitespace.

Always declare variables at the start of the function.
Don't allocate potentially large variables on the stack.
Check strsep() return values when the string comes from userland.
Shorten variable names for lucidity's sake.

most of the stuff:
Pointed out by: njl@

Finally bring in what was produced during Google SoC 2005:

Add functions to rename objects and to move a subdisk from one drive
to another.

Obtained from: Chris Jones <chris.jones@ualberta.ca>
Sponsored by: Google Summer of Code 2005
MFC in: 1 week