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)

Add support files for using text from the POSIX specification in
FreeBSD manual pages:

- POSIX-copyright contains copyright text to be used in manual pages
which has POSIX text inserted.
- deshallify.sh is a shell script which removes many of the ``shall''
statements from the POSIX text and therefore making the text more
readable.

Real work to make this happen by: nectar, ru