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 sysdoc, a small set of scripts which will parse a kernel binary and
modules to rip out the available sysctls. It will then produce a manual
page which may be installed with 'make install'. Currently typing 'make'
in the directory uses the default /boot/kernel files. To use a specific
directory, run sysdoc -k [location].