This patch adds basic CTF support and a CTF-powered pretty-printer to ddb.
It uses the features added in the first patch to load and use CTF data from ddb.
The db_ctf.* files expose a basic interface for fetching type data for ELF symbols, interacting with the CTF string table, and translating type identifiers to type data.
The db_pprint.c file uses the aforementioned interfaces to implement a pretty-printer for all kernel ELF symbols.
Additionally, the pretty printing command takes an optional 'depth' parameter, making it easy to print out specific parts of complex data types.