This allows us to define a custom mark/free function using
Data_Wrap_Struct. This in turn makes the code a bit more robust by
marking objects that are counted so they're not garbage collected by
accident.

Sometimes, for whatever reason, this output may contain instances of
objects. For example, in a test script I ended up with an Enumerable
instance in the output (which then triggers an error as Enumerable
doesn't respond to #hash). I have no idea how on earth an Enumerable can
1) get initialized since it's a module 2) ends up in the output.

In rare circumstances locking/unlocking a Mutex may lead to an object
allocation which in turn crashes CRuby when this happens during a GC
run. Since the GIL already prevents multiple Ruby threads from running
in parallel we should be able to safely remove the usage of explicit
mutexes without breaking things.

By just stuffing these into the Allocations module as a constant we can
prevent them from being GC'd.