Support compilation on OS X when Apple's blocks are used in stdlib.h, as well as fixes to CL/cl.h when CL_API_SUFFIX__VERSION_1_2 is undefined
Created by: axman6
The fix turned out to be pretty simple, just tell CPP that BLOCKS should be undefined when compiling on OS X.
Once I fixed this, I found that CL_API_SUFFIX__VERSION_1_2 was undefined when compiling on OS X, so I wrapped all function declarations in #ifdefs to avoid the issue. I'm not sure if this is the correct way to fix this, but it does work.