[rfk]

I got my acronyms wrong, it's called the "CLI" backend, but it's definitely in there: http://doc.pypy.org/en/latest/cli-backend.html

[rfk]

Heh, actually it might be possible to cheat a little with this backend as well, using http://www.jsil.org/ to translate the output of the cli backend into javascript. Trying C+Emscripten versus CIL+JSIL would be a very interesting comparison.