Remove $FreeBSD$: one-line sh pattern

Remove /^\s*#[#!]?\s*\$FreeBSD\$.*$\n/

Fix spurious error from sysrc

When using sysrc to modify a file, the file should be created silently.
However, with the introduction of SVN r335280, an error of "No such file
or directory" would appear despite everything else working as-expected.

The nature of this spurious error is that SVN r335280 did not check if
the file exists first, before trying to fixup the line-endings in the
file just prior to modification.

PR: bin/240875
Reported by: Jose Luis Duran
MFC after: 3 days

sysrc.subr: Fix a comment for accuracy

PR: bin/203435
Reported by: Andreas Sommer <andreas.sommer87@googlemail.com>
MFC after: 6 days
X-MFC-to: stable/11
X-MFC-with: r335280
Sponsored by: Smule, Inc.

sysrc.subr: Fix display when value is "-n"

PR: bin/226406
Reported by: Marius Halden <marius.halden@modirum.com>
MFC after: 1 week
X-MFC-to: stable/11
Sponsored by: Smule, Inc.

sysrc.subr: Fix handling of files with missing newline at EOF

PR: bin/203435
Reported by: Andreas Sommer <andreas.sommer87@googlemail.com>
MFC after: 1 week
X-MFC-to: stable/11
Sponsored by: Smule, Inc.

Guard against bad service name argument(s) to load_rc_config()

MFC after: 3 days
X-MFC-to: stable/11 stable/10

Add support for "rc.conf.d" file(s).

Differential Revision: https://reviews.freebsd.org/D3551
Reviewed by: allanjude
MFC after: 1 week
X-MFC-to: stable/10
X-MFC-with: 290337
Relnotes: yes

Performance and debugging enhancements:
+ Remove UNAME_P=$(...) from startup/misc -- already supplied by common.subr
+ Use f_getvar instead of $(eval echo \$$var) -- f_getvar is sub-shell free
+ Add `-e' and `-k var' options to f_eval_catch -- increasing use-cases
+ Use f_eval_catch to display errors on failure -- reducing duplicated code
+ Use f_eval_catch when we need output from a command -- improving debugging
+ Optimize f_isinter of strings.subr for performance -- now sub-shell free
+ Improve error checking on pidfiles -- using f_eval_catch and f_isinteger
+ Use $var_to_set arg of f_ifconfig_{inet,netmask} -- eliminate sub-shells
+ Use f_sprintf instead of $(printf ...) -- consolidate sub-shells
+ Use $var_to_set arg of f_route_get_default -- eliminate sub-shells
+ Add f_count to replace $(set -- ...;echo $#) -- eliminate sub-shells
+ Add f_count_ifs to replace $(IFS=x;set -- ...;echo $#) -- no sub-shells
+ Replace var="$var${var:+ }..." in loops with var="$var ..." with a follow-
up var="${var# }" to trim leading whitespace -- optimize loops
+ Use $var_to_set arg of f_resolv_conf_nameservers -- eliminate sub-shells
+ Comments for the f_eval_catch function
+ Remove a duplicate `local ... desc ...' in f_device_get_all of device.subr
+ Use $var_to_set arg of f_device_capacity -- eliminate sub-shells
+ Whitespace fixes in f_dialog_init of dialog.subr
+ Optimize f_inet_atoi of media/tcpip.subr for performance -- sub-shell free
+ In several cases, send stderr to /dev/null -- clean up runtime execution
+ Change f_err of common.subr to go to program stderr not terminal stderr,
allowing redirection of output from functions that use f_err
+ Disable debugging when using f_getvar to get variable argument to
f_startup_rcconf_map_expand of startup/rcconf.subr
+ Use f_replace_all instead of $(echo ... | tr | sed) -- performance
+ Add a $var_to_set option to f_index_{file,menusel_{command,keyword}} of
common.subr -- centralize sub-shells

Comments.

Fix typos in the BSD License.

Be consistent with other usr.sbin programs w/respect to the copyright
wording ("All rights reserved."); I had the casing wrong on many instances.

More whitespace.

Add more debugging to help with diagnosis of program-flow when needed.

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)

Allow deferred word-splitting via f_sysrc_get() by allowing $IFS in the
"clean-room" environment used to query rc.conf(5) parameters.

This brings bsdconfig(8)'s sysrc.subr in-line with both the sysrc(8) manual
[provided by sysutils/sysrc] and sysrc(8)'s own sysrc.subr (now identical to
bsdconfig(8)'s sysrc.subr as of this patch).

Finally, this will allow a clean import of sysutils/sysrc (sans sysrc.subr,
already provided here).

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

Sanitize varname argument in f_sysrc_find. This is as much for security as it
is for sanity.

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

Always use RC_CONFS when set, even if NULL. Previously only used if non-NULL.

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

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

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

Spelling and whitespace corrections.

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

Reverse SVN r240770 -- jilles@ made a suggestion that allowed us to redesign
our embedded rescue environment to support /dev/null making r240770 obsolete.

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

Replace redirections to /dev/null with "close file-descriptor" syntax (>&-).

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

Move major includes into /usr/share/bsdconfig for easy external access.

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