MFC SVN r336350: Send sysrc(8) error message to stderr (not stdout)

PR: bin/229806
Reported by: Andreas Sommer <andreas.sommer87@googlemail.com>
Sponsored by: Smule, Inc.

MFC r290337: Add sysrc(8) support for "rc.conf.d"

Differential Revision: https://reviews.freebsd.org/D3551
Reviewed by: allanjude
Relnotes: yes

MFC r287413: Minor code cleanups (no functional changes).

MFC r287390: Bump version for altered long-opts processing

MFC r287389: Simplify long-option processing

MFC r287385: Bump version for prior fix (SVN r287381)

MFC r287384:
Style: Remove whitespace around brackets from function syntax options

MFC r287383: Comment for escape() function.

MFC r287382: Comment

MFC r287381: Properly escape arguments when moving into jail or chroot

MFC r287380: Style: comments

MFC r287379: Style consistency: add single space before each `;;' case entry

MFC r287378:
Remove `SYSRC_' prefix from $SYSRC_VERBOSE (prefix unnecessary since
this is a non-inheritable attribute; was previously).

MFC r287421: Fix mandoc(1) "WARNING: end of line whitespace"

Snap to breuffer's r286660 (incorrectly merged)

MFC r287420: Remove non-functional examples.

MFC r287979:

Remove redundant beforeinstall.

MFC r281780: Update usage statement; align with post-r279624.

MFC revisions 274068, 274119, 279624:
r274068: Add key+=append syntax to sysrc(8)
r279624: Add key-=remove syntax
r274119: Add EXAMPLES-section entries for new syntax

Reviewed by: shurd (r274068)
Thanks to: seanc
Relnotes: sysrc(8) now supports key+=append and key-=remove

MFC revisions 268860, 268863:
r268860: Minor enhancements, bug fixes, and man-page adjustments.
r268863: Bump .Dd in manual

Reported by: lme
Approved by: re (gjb)

MFC r257824,257826-257830,258411: Updates to sysrc(8)
257824: Fix a bug with `-d' form working as documented
257826: Add `--version' long option
257827: Add a `-c' option for `check only'
257828: Comments and whitespace
257829: Fix a bug with `-e' introduced by above 257828
257830: Document SYSRC_VERBOSE enviroment variable in the manual
258411: Revert the above 257830 (both merged to get .Dd bump in man-page)

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

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

Fix typos in the BSD License.

Update release info.

Update copyright/date on the back of r252798.

Update sysrc(8) manual to coincide with r252797:

Do not inherit $SYSRC_VERBOSE from operating environment. The concern is
that when a user (such as myself) which has SYSRC_VERBOSE=1 in his/her
~/.bash_profile or such that when they are told to execute a command like:

hostname `sysrc -n hostname`

NOTE: To activate a recently configured hostname.

If $SYSRC_VERBOSE is set, then POLA is violated because the output of sysrc
is indirectly influenced (making for an inconsistent experience).

Do not inherit $SYSRC_VERBOSE from operating environment. The concern is
that when a user (such as myself) which has SYSRC_VERBOSE=1 in his/her
~/.bash_profile or such that when they are told to execute a command like:

hostname `sysrc -n hostname`

NOTE: To activate a recently configured hostname.

If $SYSRC_VERBOSE is set, then POLA is violated because the output of sysrc
is indirectly influenced (making for an inconsistent experience).

Remove NO_OBJ from Makefiles that generate manuals because this causes the
GZIP compressed manuals to appear in ./src instead of the appropriate obj dir.

PR: conf/175844
Submitted by: Dominique Goncalves <dominique.goncalves@gmail.com>

Mirror the changes made in SVN r240798:

Replace "( : ${var?} )" syntax with better "[ ${var+set} ]" syntax.

Reviewed by: adrian (co-mentor)
Approved by: adrian (co-mentor)

mdoc: begin sentences on a new line.

Minor mdoc fix.

Remove trailing whitespace.

Fix HISTORY.

Sort manual page cross references.

Approved by: joel (mentor)

Remove whitespace at EOL

Approved by: joel (mentor)

Import sysutils/sysrc from the ports tree (current version 5.1). Importing
disconnected under the WITH_BSDCONFIG flag (a good idea since this version of
sysrc(8) indeed requires the `sysrc.subr' module installed by bsdconfig(8)).

Multiple reasons sysrc should not simply continue to live in ports. The most
important being that it is tightly coupled with the base.

Approved by: adrian (co-mentor)