[clang] [OpenCL] Allow undefining cl_khr_integer_dot_product features macros (PR #162055)

[Sven van Haastregt via cfe-commits]

svenvh wrote:

> For simplicity, can we revert https://reviews.llvm.org/D92231 and don't always define the feature macro in headers?

Not really, reverting that does not solve the underlying issue and would be a step backwards regarding moving header-only extensions out of the Clang internals.  If I understand correctly, the underlying issue is that historically the `SPIR` target had become the equivalent of "enable all known extensions".  Perhaps that's something we'd want to reconsider, but that's a separate discussion.

https://github.com/llvm/llvm-project/pull/162055