Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

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

MFC r258270:

Add a try-include word (which acts the same as "include") and use it to
conditionally include (but ignore failures) /boot/loader.rc.local and
/boot/menu.rc.local -- to make customizing the menu easier.

Reviewed by: alfred
Discussed on: -hackers

MFC r257650:

Defer loading of kernel and modules if the beastie menu is enabled. Add a
kernel selection menu to the beastie menu. List of kernels is taken from
`kernels' in loader.conf(5) as a space (or comma) separated list of names
to display (up to 9). If not set, default value is "kernel kernel.old".
Does not validate that kernels exist because the next enhancement will be
to allow selection of the root device.

Discussed on: -current

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

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

Since the introduction of SVN r244048 and [follow-up] r244089, it is now
safe to build upon ``boot_serial?'' functionality to make safer UI choices.

Discussed at-length on -arch.

Make the following interface changes to my beastie boot menu:
+ Move boot options to a submenu
+ Add a new "Boot Single" menu item
+ Make "Boot" item and new "Boot Single" item reverse when boot_single is set
+ Add new "Load Defaults" item (in new "Boot Options" submenu) for overridding
loader.conf(5) provided values with system defaults.

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

Since the introduction of the new advanced boot menu (r222417), options like
"boot verbose", "single user mode", "ACPI" and more are now stateful boolean
menuitems rather than direct action-items.

A short-coming in this new menu system is that when a user sets a non-default
value in loader.conf(5), this non-default state is not reflected in the menu
-- leading to confusion as to whether the option was taking effect or not.

This patch adds dynamic menuitem constructors _and_ the necessary Forth
callbacks to initialize these stateful menuitems -- causing the aforementioned
menuitems to adhere to loader.conf(5) settings.

PR: bin/172529
Approved by: adrian (co-mentor)
MFC after: 21 days

Clarify and improve the boot menu with some small changes:
- Enter instead of ENTER
- Remove colons
- Line up option values
- Use dots to provide a line to visually connect the menu
selections with their values
- Replace Enabled/Disabled with off/On
(bigger inital cap for "On" is a visual indicator)
- Remove confusing "Boot" from selections that don't boot.
- With loader_color=1 in /boot/loader.conf, use reverse video to
highlight enabled options

PR: misc/160818
Submitted by: Warren Block <wblock wonkity com>
Reviewed by: Devin Teske <devin dot teske fisglobal com>, current@
MFC after: 1 week

New boot loader menus from Devin Teske.
Discussed on hackers and recommended for inclusion into 9.0 at the devsummit.
All support email to devin dteske at vicor dot ignoreme dot com .

Submitted by: dteske at vicor dot ignoreme dot com
Reviewed by: me and many others