This does about the minimum necessary for assembly analysis to work. It assumes
that any function it hasn't been able to analyse itself needs 512 bytes (most
need far less); it doesn't do any flow analysis; it doesn't do a lot of sanity
checking. However, it produces sensible numbers, and works with the demos I've
tried so far.
I was originally going to make this a separate tool, but there are a number of
bits of the code can be nicely reused, so it's a separate "operating mode" in
the existing program (as is parse-only mode now).
