Often times when using mdb, people run into situations where they either don't have CTF data or there are anonymous structures being used in such a way that no DWARF and thus no CTF data for them is ever emitted. To help deal with this, we introduce ::typedef as a way to create synthetic CTF types. ::typedef creates introduces a private, writeable, CTF container to mdb. It also adds support for viewing these types to the various mdb_ctf_* apis. This allows things like tab completion, ::print, and others to know that they exist and find them.