Add setup command for building a static python interpreter with pyvex.

This is a giant hack to get around the fact that libvex comes as a
static library for most valgrind distributions (debian/ubuntu). It is
not compiled -fPIC so it is not possible to make a shared object
extension unless libvex is recompiled.

This is one of the more disgusting things I have written in recent memory. I don't know if this will be useful to anyone else but I decided to send it along regardless.