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)

Style improvements recommended by Bruce as a follow up to some
of the recent WARNS commits. The idea is:

1) FreeBSD id tags should follow vendor tags.
2) Vendor tags should not be compiled (though copyrights probably should).
3) There should be no blank line between including cdefs and __FBSDIF.

Use __FBSDID()

WARNS=2 fixup.

Expland `mymalloc' with malloc + error checking.

Correct use of .Nm, .Em, .Ev
Add rcsid. Use errx instead of fprintf + exit.
Various spelling fixes.

$Id$ -> $FreeBSD$

(1) Don't perror() when at.deny doesn't exist, that's an accepted behavior.

(2) Die when there is a problem opening at.allow other then it not existing.
An error other then it not existing might be a trick to somehow
circumvent system security.

Mostly Reviewed By: msmith

Eliminate compiler warnings from -Wall

Revert $FreeBSD$ to $Id$

Make the long-awaited change from $Id$ to $FreeBSD$

This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.

Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.

Upgrade to 2.9

Remove trailing whitespace.

Upgrade.