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

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

Revert r327005 - SPDX tags for license similar to BSD-2-Clause.

After consultation with SPDX experts and their matching guidelines[1],
the licensing doesn't exactly match the BSD-2-Clause. It yet remains to be
determined if they are equivalent or if there is a recognized license that
matches but it is safer to just revert the tags.

Let this also be a reminder that on FreeBSD, SPDX tags are only advisory
and have no legal value (but IANAL).

Pointyhat to: pfg
Thanks to: Rodney Grimes, Gary O'Neall

[1] https://spdx.org/spdx-license-list/matching-guidelines

SPDX: These are fundamentally BSD-2-Clause.

They just omit the introductory line and numbering.

SPDX: mostly fixes to previous changes.

Introduce the recently approved BSD-1-Clause and replace 0BSD which
never did fit well our use cases.

SPDX: Fix some cases wrongly attributed to MIT.

In the cases of BSD-style license variants without clauses, use 0BSD for
the time being in lack of a better description.

sys/sys: further 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.

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

Slightly change the API for the SNPSTTY ioctl so that the userland now
provides a file descriptor instead of a dev_t.

Discussed with: phk
MFC after: 3 days

/* -> /*- for license, minor formatting changes

Second half of the dev_t cleanup.

The big lines are:
NODEV -> NULL
NOUDEV -> NODEV
udev_t -> dev_t
udev2dev() -> findcdev()

Various minor adjustments including handling of userland access to kernel
space struct cdev etc.

Declare the snp ioctl()s to work on udev_t, since that is what they
really do and dev_t is defined differently in kernel and userland.
Return a correctly formed udev from SNPGTTY.

Reviewed by: dd

- Spell "these" properly.

Include <sys/types.h> in the !_KERNEL case so that this file is
self-sufficient in that case (it needs dev_t). This is normal pollution
for most headers that define ioctl numbers.

Move the kernel stuff out of snoop.h. It was only there because some
of the snp* functions needed to be called from tty.c, which is no
longer the case.

Keep track of all "struct snoop"'s so that snp_modevent can fail with
EBUSY if there's a device still open.

Style and cosmetic cleanups. This driver is now reasonably stlye(9)
compliant. All the variable definitions and function names are
reasonably consistent, and the functions which should be static (i.e.,
all of them) are. Other assorted fixes were made. The majority of
the delta is indentation fixes.

Partially reviewed by: bde

Remove unused includes, use *min() inline functions rather than a
home-grown macro, rewrite a confusing conditional in snpdevtotty(),
and change ibuf to 512 bytes instead of 1024 bytes in dsnwrite().

Reviewed by: bde

Add snp_olddisc member to struct snoop; the linedisc'ized snp(4) uses this.

Pointy hat to: dd

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.

Seventy-odd "its" / "it's" typos in comments fixed as per kern/6108.

Fixed nonblocking mode. It was per-device instead of per-file.

Only export ioctl-related stuff to applications. Include prerequisite
headers (like most other ioctl-related headers).

Didn't fix spelling errors and other warts.

A Major staticize sweep. Generates a couple of warnings that I'll deal
with later.
A number of unused vars removed.
A number of unused procs removed or #ifdefed.

Moved prototypes for devswitch functions from conf.c and driver sources
to <machine/conf.h>. conf.h was mechanically generated by
`grep ^d_ conf.c >conf.h'. This accounts for part of its ugliness. The
prototypes should be moved back to the driver sources when the functions
are staticalized.

Fix benign type mismatches in devsw functions. 82 out of 299 devsw
functions were wrong.

Remove trailing whitespace.

Add and move declarations to fix all of the warnings from `gcc -Wimplicit'
(except in netccitt, netiso and netns) that I didn't notice when I fixed
"all" such warnings before.

same

(a) remove the pointer to each driver's tty structure array from cdevsw
(b) add a function callback vector to tty drivers that will return a pointer
to a valid tty structure based upon a dev_t
(c) make syscons structures the same size whether or not APM is enabled so
utilities don't crash if NAPM changes (and make the damn kernel compile!)
(d) rewrite /dev/snp ioctl interface so that it is device driver and i386
independant

More changes to support user calls.

Add more flags to snoop device

TS_SNOOP flag added to identify tty is begin snoopped
snoop.h have all structures related to the snp device and stuff