PHP added this in 5.4 so that you can say your closure shouldn't capture ##$this##. https://wiki.php.net/rfc/closures
Should we add it? Many of their unit tests use it.
Instead of putting a boolean somewhere I used the same attr framework and set the static bit there. Thoughts? It only needs one change in the ##FPushFunc##.
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.
ptarjan