Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

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

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Good thing about these examples is that no one uses them, so they can
stay broken for months without anyone noticing.

The boot-conf command was changed as to reproduce the behavior of builtin
loader words precisely. As a result, it now always need an argument, possibly
0 indicating that no other arguments are being passed. This broke in a
non-deterministic way (ie, it could go on working as if everything was fine).

Fixes a silly bug that somehow escaped my notice all these months.

$Id$ -> $FreeBSD$

Rewording.

Add a menu example making use of loader.4th(8) facilities.

Merge candidate, as it is just an example...