=== Adding basic CTF support to ddb

Links: +
link:https://reviews.freebsd.org/D37898[Differential 1] URL: link:https://reviews.freebsd.org/D37898[https://reviews.freebsd.org/D37898] +
link:https://reviews.freebsd.org/D37899[Differential 2] URL: link:https://reviews.freebsd.org/D37899[https://reviews.freebsd.org/D37899]

Contact: Bojan Novković <bojan.novkovic@kset.org>

The goal of this project was to extend the ddb kernel debugger to use the kernel's Compact C Type Format (CTF) data and use the newly added features to implement a pretty-printing command in ddb.

Due to a restrictive execution environment (no IO or memory allocation), ddb can not use existing kernel linker methods to retrieve the kernel's CTF data.
Instead, the first patch adds the ability to load the kernel's CTF data during boot and adds a new kernel linker method used for accessing CTF data from ddb.
The second patch adds a basic interface for using CTF data in ddb and a pretty-printing command built using the newly added interfaces.

Any feedback, comments, and reviews are welcome and would be greatly appreciated.