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

Eliminate sub-shells where possible for performance.

MFC after: 7 days

Default `bsdconfig timezone' and `tzsetup' to `-s' in a VM.

Recommended by: cperciva
Reviewed by: cperciva
Relnotes: tzsetup and bsdconfig now assume that the "hardware" clock inside a VM is set to UTC

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

Introduce centralized [X]dialog(1) exit codes to `dialog.subr' and make-use
throughout the bsdconfig(8) code. While we're here, add an explicit argument
to lvalue-seeking invocations of "return" that previously had no argument.
Also, consolidate a single instance of double-newline and remove some
comments that are no longer required (given increased readability with new
exit codes).

Approved by: re (glebius)

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.

Take advantage of newly updated f_dialog_{yesno,noyes}() functions from
SVN r251977 (adding an $hline parameter).

Standardize the way functions build their arguments leading up to a dialog
invocation. Specifically, "top-load" your arguments and in the order in-
which they will be displayed. For example, many [if not all] widgets display
information in the following order, top-to-bottom (visually):

+ backtitle (displayed behind the widget at top-left)
+ title (at the top of the `window')
+ prompt text (just below the title and above whatever widget you choose)
+ Depending on widget, _one_ of the following:
- menu list
- radio list
- check list
- text input box with initial text
- [Xdialog(1)] 2x or 3x text input boxes
- [dialog(1)] a multi-part form
- progress bar
- etc. (many more widget choices)
+ buttons (right below the selected widget)
+ [dialog(1)] the hline (displayed at bottom of `window')

NOTE: Xdialog(1) accepts and silently ignores --hline

When building local arguments for your dialog invocation, if the value can't
be cleanly loaded into a local, add "# Calculated below" to the end of the
local declaration while retaining the block order of argument declarations.

Move other local declarations that are not associated with this top-loading
the dialog arguments to right-above where they are first-used.

Also, standardize on the names of the arguments. For example, always use
$prompt (instead of sometimes $msg and sometimes $prompt); use $menu_list
or $shell_list or $radio_list for those respective widgets; ad nauseum.

While we're doing this, flush-out full arguments for many invocations that
were passing NULL strings (making it unapparent if you were staring at this
one invocation what argument that NULL string was supposed to represent).

Last, while we're in startup/rcconf let's remove the unnecessary use of a
GLOBAL (RCCONF_MENU_LIST) for the menu_list.

Improve the dialog(1) API in dialog.subr by adding f_dialog_default_store()
and f_dialog_default_fetch(). Operating similar to functions introduced by
SVN r251236 and r251242, these functions operate as a pair for helping track
the default-item data (for the --menu, --checklist, and --radiolist
widgets).

This replaces the direct usage of a global to store the data with an
abstract method for readability and to centralize the code.

Improve portion of the dialog(1) API in dialog.subr responsible for
retrieving stored data (for the --menu, --calendar, --timebox, --checklist,
and --radiolist widgets).

When we (Ron McDowell and I) developed the first version of bsdconfig, it
used temporary files to store responses from dialog(1). That hasn't been
true for some very long time, so the need to always store the return status
of dialog(1) and then call some function to clean-up is long-deprecated. The
function that used to do the clean-up was f_dialog_menutag().

We really don't need f_dialog_menutag() for its originally designed purpose,
as all dialog invocations (even when in a sub-shell) do not use temporary
files anymore.

However, we do need to keep f_dialog_menutag() around because it still fills
the need of being able to abstract the procedure for fetching stored data
provided by functions that display the aforementioned widgets.

In re-designing f_dialog_menutag(), four important changes are made:

1. Rename f_dialog_menutag() to f_dialog_menutag_fetch()
2. Introduce the new first-argument of $var_to_set to reduce number of forks
3. Create a corresponding f_dialog_menutag_store() to abstract the storage
4. Offload the sanitization to a new function, f_dialog_data_sanitize()

NOTE: That last one is important. Not all functions need to store their data
for later fetching, meanwhile every invocation of dialog should be sanitized
(as we learned early-on in the i18n-effort -- underlying libraries will spit
warnings to stderr for bad values of $LANG and since dialog outputs its
responses to stderr, we need to sanitize every response of these warnings).

These changes greatly improve readbaility and also improve performance by
reducing unnecessary forking.

Fix a typo introduced by r251190.

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).

Centralize standard getopts arguments, both for convenience and to correct
a bug in which certain combinations of arguments produced unexpected results
such as `-dX' (now properly produces debugging and X11), `-XS' (now properly
produces X11 in secure mode), `-df-' (enables debugging when reading a
script from standard-input, etc. Multi-word variations such as `-d -X',
`-X -S', `-d -f-', `-d -f -', etc. also work as expected. Also tested were
variations in argument order, which are now working as expected.

UI improvements. First, implement --default-item whenever and wherever
possible to save keystrokes. Second, overhaul startup/rcdelete for much
improved performance. Last, but not least, kill-off useage of --clear
and implement --keep-tite in harmony to minimize jarring transitions.
Also, fix local variable names where necessary while we're here with
other minor comment-enhancements/typo-corrections.

Add new flags `-d' (sets debug=1) and `-D file' (sets debugFile) and
improve debugging initialization. Also fixup USAGE statements while we're
here. Also, change initialization of main program to _not_ change working
directory, allowing the debugFile to be relative without confusion.

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

Remove unnecessary duplicate initialization of the dialog(1) API (automatically
bootstrapped on-include unless DIALOG_SELF_INITIALIZE is set to NO before-hand)

Replicate a feature from sysinstall documented in
stable/9/usr.sbin/sysinstall/help/shortcuts.hlp (reproduced below):

If /usr/sbin/sysinstall is linked to another filename, say
`/usr/local/bin/configPackages', then the basename will be used
as an implicit command name.

To get a list of modules you can link to, see `bsdconfig -h' output.

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

Change all invocations of dialog(1) to no-longer require temporary files.
This allows bsdconfig to -- like bsdinstall -- operate from read-only media.

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)