[Bf-python] Rpython to LLVM

[Dan Eicher]

Seems to me that it'd be a lot easier to just hook some module
building mechanism into cmake/scons for any extensions that would need
to have compiled code. That would mostly take care of the 18 platform
building issue mentioned too.

Also be possible to add cython to the mix with a patch I have floating
around that gets makesrna to spit out cython bindings for the C++ api
(along with the mentioned build system hooks).

Dan