I have just finished updating the OpenCL bindings and the VirtualGPU to use the UnifiedFFI in Pharo 5. All of the examples have been tested in Mac OS X El Capitan 10.11.6.
Available at: http://smalltalkhub.com/#!/~ronsaldo/VirtualGPU
P.S: Do not confuse the VirtualGPU with the AbstractGPU. The AbstractGPU is an abstraction layer above Vulkan, Direct3D 12 and Metal. The AbstractGPU is used as the foundation for Woden 2.