[patch] initial OpenCL C language support

[Joel Brobecker]

> I have a few comments, and I feel like most of the changes except maybe
> the ones in c-exp.y can go in without a followup review.

Just to clarify a bit what I was trying to say: Most of the comments are
mostly cosmetic, and I don't think we need to verify that you followed
the comments correctly. If this was the only comments I had, I would be
comfortable with pre-approving the patch, particularly since Tom already
looked at it as well.  But before the patch goes in, I'd like to understand
what the reason for the changes in c-exp.y...

-- 
Joel