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)

Designate special builtins as such in command -V and type.
Also document various properties of special builtins that we implement.

Approved by: ed (mentor) (implicit)

Set magic fbsd:nokeywords property that allows files to bypass
keyword expansion. (file-specific replacement for CVSROOT/exclude)

Add test cases for the command built-in, including its -v and -V options which
I'll commit real soon.

Count the number of found test cases instead of hard-coding them. Allow an
arbitrary exit status.