Backport OpenCL fixes that was only committed to bleeding.
Revert "OpenCL: Change the -DAPPLE for OpenCL build options to -D__APPLE__."

This reverts commit f7e80bb189f8d6524a1311f27689dc88b4a26091.
Fixes to keychain-opencl, strip-opencl and agilekeychain-opencl that were
only applied to bleeding.