Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

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

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

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.

Change a humongous if-statement at the end of f_install_zoneinfo_file() into
an early return, allowing a huge chunk of code to be indented one-level less

When I first wrote the timezone module, it was in sysutils/tzdialog and it
pre-dates bsdconfig. Update the code to take advantage of f_dialog_msgbox().

Improve portion of the dialog(1) API in dialog.subr responsible for
calculating widget sizes. Instead of forking a sub-shell to calculate the
optimum size for a widget, use a byRef style call-out to set variables in
the parent namespace. For example, instead of:

size=$( f_dialog_buttonbox_size title btitle msg )
$DIALOG --title title --backtitle btitle --msgbox msg $size

The new API replaces the above with the following:

f_dialog_buttonbox_size height width title btitle msg
$DIALOG --title title --backtitle btitle --msgbox msg $height $width

This reduces the number of forks, improves performance, and makes the code
more readable by revealing the argument-order for widget sizing. It also
makes performing minor adjustments to the calculated values easier as
you no longer have to split-out the response (which required knowledge of
ordering so was counter-intuitive).

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

Whitespace.

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

jilles accurately advises that, in the context of shell redirection, the `:'
builtin is processed specially and thus the `: > file' syntax for example
will cause premature termination of the current shell on redirection-error.

The `true' builtin on the other-hand is not included in this special
processing (for compatibility reasons to satisfy legacy scripts programmed
for systems where `true' is not a builtin).

Change bare `: > file' syntax into `true > file' syntax to prevent premature
shell termination in the event of redirection-error.

NOTE: Instances of `: > file' that appear within a sub-shell have been left
unmodified as these will not cause premature termination of the main script.

Reviewed by: jilles, 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)

Import bsdconfig(8) as a replacement for the post-install abilities of
deprecated sysinstall(8). NOTE: WITH_BSDCONFIG is currently required.

Submitted by: Devin Teske (dteske), Ron McDowell <rcm@fuzzwad.org>
Reviewed by: Ron McDowell <rcm@fuzzwad.org>
Approved by: Ed Maste (emaste)