Purge more stray embedded $FreeBSD$ strings

These do not use __FBSDID but instead use bare char arrays.

Reviewed by: imp, emaste
Differential Revision: https://reviews.freebsd.org/D41957

Mark usage function as __dead2 in programs where it does not return

In most cases, usage does not return, so mark them as __dead2. For the
cases where they do return, they have not been marked __dead2.

Reviewed by: imp
Pull Request: https://github.com/freebsd/freebsd-src/pull/735

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD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

fts_read: Handle error from a NULL return better.

This is addressing cases such as fts_read(3) encountering an [EIO]
from fchdir(2) when FTS_NOCHDIR is not set. That would otherwise be
seen as a successful traversal in some of these cases while silently
discarding expected work.

As noted in r264201, fts_read() does not set errno to 0 on a successful
EOF so it needs to be set before calling it. Otherwise we might see
a random error from one of the iterations.

gzip is ignoring most errors and could be improved separately.

Reviewed by: vangyzen
Sponsored by: Dell EMC
Differential Revision: https://reviews.freebsd.org/D27184

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.

Constify return value of stripath and avoid unnecessary deconst
casts.

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

- Align the function prototype of the external `crc' function with
how `crc' is actually defined.
Data type corrections:
- Define variables which contain file byte offset values as type
off_t as required by the `crc' function.
- Change the type of a variable carrying a CRC checksum from `u_long'
to `uint32_t'.
- Parse the length of a file with sscanf as `intmax_t'
(as there is no conversion specifier for `off_t').
Style(9):
- Put an empty line between #include directives for system and user
header files.

match prototype

$Id$ -> $FreeBSD$

Put includes in alphabetical order. various cosmetics.

ckdist - a handy utility for verifying the sanity of a distribution.

This will probably need to go away again someday when distributions get
folded into packages and there are no more dist files to check, but knowing
how long we've been waiting on THAT, this will be a welcome tool for the
interim.
Submitted by: Robert Nordier <rnordier@iafrica.com>