Tool to find unused functions in Tor

We should periodically check for dead functions in Tor, and remove them.

We should have a tool to find them for us.

We could use the cruddy approach I used to take, which I can no longer find the perl script that I used to have implement. I'll attach a cruddy implementation of that one.

We could use a tool like http://www.skynet.ie/~caolan/Packages/callcatcher.html , if that actually works, and turns out not to be stupid if I read about it for more than 60 seconds.

Other suggestions welcome, but please think of testing them before recommending them. :)