Develop

Created by: acowley

I've been developing the CLUtil library that builds on OpenCL.

There are several patches contained in this pull request as I'd like to get my fork back in sync with upstream.

• I use the system-installed Framework on Mac OS X rather than the included headers. This covers both headers and libraries for mac builds.
• I commented out the extra-libraries line in the test suite definition because it prevents cabal install from working on Macs. I think it is more likely someone wanting to run cabal test will be willing to unpack the source than the typical user who will just want to cabal install opencl. I did file a bug report about this on cabal-install's trac some time ago, and will try to follow up about getting it fixed (i.e. if --enable-tests is not set, the extra-libraries shouldn't matter).
• I let clEnqueueNDRangeKernel take an empty list for the local work size argument. This is translated into passing OpenCL a null pointer for this argument, which, according to the spec, means "...the OpenCL implementation will determine how to be[sic] break the global work-items into appropriate work-group instances."
• I fixed the test file to use the new clSetKernelArgSto.
• I added an export for the CLMapFlag type and constructors as they are useful when mapping buffers.

I'm happy to further discuss any of these changes.