On the back burner I've been working on a diff to pull out of some of
the old VM-incompatible machinery for invoking functions/methods and for
creating object. Along the way I noticed some bugs, so I figured I'd fix
them first in a separate diff to make review easier.
This change is mostly for FB internal organizational reasons.
Building is not effected beyond the fact that the target now
lands in hphp/hhvm/hhvm rather than src/hhvm/hhvm.