Support compilation to object files

[0xekez]

Having a JIT is nice and makes testing pretty easy but at the end of the day the ability to compile to native object files is very important to me because it opens up the possibility of writing a self hosting version of Lust (this is very far down the line though.)

A branch of the simple jit demo shows approximately how this is done. Based on this I don't believe that doing this will require too much additional work as the architecture seems to be similar enough.

[0xekez]

This would help with the compilation slowdown that we see related to #18. If we could just compile all of the builtins as part of a lust installation and link them in that would remove the performance penalty that we suffer as a result of needing to compile all of them on every program run.