Unfortunately, future builds in Mac may not contain OpenCL support (due to Mac bad drivers that doesn't compile OpenCL kernels for Cycles and requires many work arounds that are not a real solutions, while they run fine on Windows and Linux!), and Apple won't help (it is all in Apple's hands, nothing we can do).
Pro Render is a different story, it is maintained by AMD, so they do the work arounds internally (possibly write assembly code for areas that Mac compiler fails in!!), this is not pratcical and shouldn't be the case (if compiler can't compile a working code, then it is not a real compiler...it is just a bugged compiler that Apple was so lazy to fix, so they just went into creating their own API for GPGPU which is Metal, and they forgot about the more important one which is OpenCL..).
the current core that we use is from October which still supports OpenCL on Mac, but on Release it will be the latest core which doesn't support OpenCL on Mac anymore.
as I know how Cycles core is done, extending it to a different API (like Metal) can be done, but it will never happen 🙂 (as it is simply not a cross platform solution).
as I know Blender users will rage also about this, so only Apple should reply with a solution for their bad drivers. or they ship NVIDIA GPUs.
I recommend, always buy PC whenever you can, with NVIDIA GPU.