Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

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

I forgot to bump the manpage date.

Reminded by: Garrett Cooper
MFC after: 3 days
X-MFC-with: r235297

Add a -v and -N option to kenv(1), so it can be more easily used in
scripts the way sysctl(8) is. The -N option, like in sysctl(8),
displays only the kenv names, not their values. The -v option prints an
individual kenv variable name with its value as name="value". This is
the inverse of sysctl(8)'s -n flag, since the default behaviour of
kenv(1) is already like sysctl(8) -n.

Submitted by: Garrett Cooper < yanegomi AT gmail DOT com >
MFC after: 1 week

Remove superfluous paragraph macro.

mdoc(7) markup.

Approved by: avg (mentor), kib (mentor)
MFC after: 3 days

o Fix a typo. Bump .Dd for the previous delta.

fix typo

Submitted by: Colin Percival

Document how kernel environment can be statically compiled in,
and reference a few related manpages.

MFC after: 3 days

-mdoc sweep.

Add a "-q" quiet flag to kenv so that warnings can be suppressed.

MFC after: 1 week

/*- or .\"- or #- to begin license clauses.

kenv(1) has been repo copied from usr.bin to bin.
Sometimes we need kenv(1) in /etc/rc.diskless*.

mdoc(7) police: punctuation.

Add a reference to the kenv(2) manpage.

Use the new functionalities provided by the kenv(2) syscall.

Reviewed by: peter

mdoc(7) police: markup nits.

Spell "FreeBSD" with "F" and "BSD" in uppercase.

mdoc(7) police: removed HISTORY info from the .Os call.

kenv(1) first appeared in FreeBSD 4.1.1, not FreeBSD 5.0.

PR: 23020
Submitted by: Simon Dick <simond@irrelevant.org>

mdoc(7) police: use the new features of the Nm macro.

Initial kenv(1) hack for dumping the kernel environment. This can be
used to extract modified boot hints to make loader(8)-time changes
"sticky". It tries to use \ style quoting so that it can be used directly
with foo.conf files. It can also extract specific variables.