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

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

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

Prepare for the removal of set_rcvar() by changing the rcvar=
assignments to the literal values it would have returned.

The concept of set_rcvar() was nice in theory, but the forks
it creates are a drag on the startup process, which is especially
noticeable on slower systems, such as embedded ones.

During the discussion on freebsd-rc@ a preference was expressed for
using ${name}_enable instead of the literal values. However the
code portability concept doesn't really apply since there are so
many other places where the literal name has to be searched for
and replaced. Also, using the literal value is also a tiny bit
faster than dereferencing the variables, and every little bit helps.

This change does the following for the scripts that run up through
FILESYSTEMS (the default early_late_divider):
1. Move sysctl to run first
2. Move as many BEFOREs to REQUIREs as possible.
3. Minor effect, move hostid_save from right before mdconfig to right
after.

A lot of the early scripts make use of sysctl one way or another so
running this first makes a lot of sense given that system-critical
values are often placed in sysctl.conf.

My original purpose for working on this was that while doing some
debugging on other stuff I noticed that the order of execution was
different in the first pass through the early scripts and the second.
In practice that doesn't matter because the scripts are not executed the
second time. However this _can_ result in problems if the difference in
the rcorder moves a script from the late section to the early section in
the second pass (which would mean the script would not get executed).
So, I wanted to make the order of execution of the scripts in the early
section more deterministic.

In the course of debugging the ordering problems I noticed that moving
the BEFOREs to REQUIREs prevented the changes in order from the first
pass to the second pass without having to make any substantial changes.
(Of course it's no secret that I think BEFORE should be avoided as much
as possible, but this is a good example of why.)

Reviewed by: silence on freebsd-rc@
MFC after: 8.1-RELEASE

As previously discussed, add the svn:executable property to all scripts

Use the new command file feature of ddb(8) to support setting ddb(4)
scripts at boot. This is currently disabled by default. /etc/ddb.conf
contains some potentially reasonable default scripts.

PR: conf/119995
Submitted by: Scot Hetzel <swhetzel at gmail dot com> (Earlier version)
X-MFC after: textdumps