Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

MFC r233648:
Remove trailing whitespace per mdoc lint warning

Approved by: cperciva (implicit)

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Fix a few typos and style nits in the example code.

Submitted by: Arnaud Lacombe lacombar of gmail
MFC after: 3 days

Update the sysctl_ctx_init(9) manual page with the following
information from the submitter:

Starting value for OID_AUTO was changed from 100 to 256 (0x100) in
kern/kern_sysctl.c#rev1.112 on 2001-07-25, and defined as
CTL_AUTO_START in sys/sysctl.h#rev1.98.

Submitted by: cnst
Silence from: #bsddocs on efnet
MFC After: 3 days
Approved by: re (bmah)

Add a basic man page for the sysctl(9) macro interfaces. Previously man
pages existed only for the dynamic sysctl interfaces. There's probably
more complete and accurate content, better advice, etc, that could be added
here.

Per scottl's suggest, add a small piece of moralizing text regarding the
fact that sysctl names quickly get embedded in system configuration files,
libraries, third party applications, and even books, so renaming and
removing names after they've been published is a tricky issue.

MFC after: 1 month

Mechanically kill hard sentence breaks and double whitespaces.

Fix some syntax errors in examples. These were discovered when trying
to follow the examples concerned.

ispell sweep of share/man/man9/*.

mdoc(7) police: Use the new .In macro for #include statements.

MFS: in HISTORY section, fix release number of first appearance

Removed whitespace at end-of-line; no content changes. I simply did
cd src/share; find man[1-9] -type f|xargs perl -pi -e 's/[ \t]+$//'

BTW, what editors are the culprits? I'm using vim and it shows
me whitespace at EOL in troff files with a thick blue block...

Reviewed by: Silence from cvs diff -b
MFC after: 7 days

mdoc(7) police: normalize .Nd.

Fixed missing and/or wrong and/or extra includes in synopsis.

mdoc(7) police: use canonical form of .Dd macro.

Use FreeBSD.org, not freebsd.org, as has been the precedent.

Clean up this new manual page. This delta includes content and
whitespace changes, which should not be a problem because this
is only the second revision of the file and translators are
unlikely to have gotten started yet.

Reviewed by: abial

These patches implement dynamic sysctls. It's possible now to add
and remove sysctl oids at will during runtime - they don't rely on
linker sets. Also, the node oids can be referenced by more than
one kernel user, which means that it's possible to create partially
overlapping trees.

Add sysctl contexts to help programmers manage multiple dynamic
oids in convenient way.

Please see the manpages for detailed discussion, and example module
for typical use.

This work is based on ideas and code snippets coming from many
people, among them: Arun Sharma, Jonathan Lemon, Doug Rabson,
Brian Feldman, Kelly Yancey, Poul-Henning Kamp and others. I'd like
to specially thank Brian Feldman for detailed review and style
fixes.

PR: kern/16928
Reviewed by: dfr, green, phk