usr.bin: 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

Remove $FreeBSD$: one-line .c pattern

Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\n/

Follow r329348 in ipcs for getting rid of the requirement to include SysV IPC
headers with _KERNEL

Reviewed by: jhb
Differential Revision: https://reviews.freebsd.org/D14398

Remove unused include.

MFC after: 2 weeks

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.

ipcs: fix builds that use gcc
gcc gets annoyed by duplicate declarations

Reported by: sbruno
Reviewed by: sbruno

ipcs: fix warnings (WARNS=1 -> WARNS=6)
- fix shadow warnings
- change type from off_t to size_t which is more correct and avoids
signed/unsigned compare
- use new initializer format to avoid "missing values" warning

Reviewed by: jhb

Spelling fixes for usr.bin/

Remove semaphore map entry count "semmap" field and its tuning
option that is highly recommended to be adjusted in too much
documentation while doing nothing in FreeBSD since r2729 (rev 1.1).

ipcs(1) needs to be recompiled as it is accessing _KERNEL private
variables.

Reviewed by: jhb (before comment change on linux code)
Sponsored by: Sandvine Incorporated

Use %zu when printing size_t.

MFC after: 1 month

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

Make the char *n_name member of struct nlist 'const'.
This avoids errors or __DECONST() from places with higher WARNS levels.

Adjust a local cache variable in ipcs to const as well
to compile in the new world order.

Suggested by: jhb
Reviewed by: jhb, kib, brueffer (man)

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.

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

Add the ability to clean up all shared memory segments which are
unused in one go.

From the original PR:

I've observed that linux apps running under the linuxulator
have a habit of leaving behind shared memory segments which
are unused, but which eventually cause the system to run
out of free segments and these apps will stop working.
ipcrm(1) currently only allows removal of unused message
queues, shared memory segments and semaphores on an individual
basis, or those having a matching (non-zero) key. However
it would often be convenient to just do a complete cleanup
of everything, usually as root.

PR: bin/118292
Submitted by: Callum Gibson <callumgibson@optusnet.com.au>
Not reviewed by: grog@
Approved by: grog@