[libclc] [libclc] Add custom CMake language handling for OpenCL files (PR #185243)

[Joseph Huber via cfe-commits]

jhuber6 wrote:

> LGTM. Thanks @jhuber6 for the effort.

No problem, https://github.com/llvm/llvm-project/pull/185247 is the complicated one. Still, this should be a big reduction in CMake complexity I feel. Doing basic checks it seems the output libraries are as they should be, but I don't know every single possible config.

https://github.com/llvm/llvm-project/pull/185243