[PATCH] Permit OpenCL event_t's to be constructed from integer value 0.

[Neil Henning]

  Thanks for the comments!

  Its very obscure in the spec, but if you look at the functions that use event_t types, like [[ https://www.khronos.org/registry/cl/sdk/1.1/docs/man/xhtml/async_work_group_copy.html | async_work_group_copy ]] it says 'The event argument can also be used to associate the async_work_group_copy with a previous async copy allowing an event to be shared by multiple async copies; otherwise event should be zero'.

http://llvm-reviews.chandlerc.com/D2860