This is the first part of the work to expose type constraint and generic all the way to reflection. This first DIFF exposes the return type with generic types coming next.
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.