[libclc] [libclc] Track dependencies through dependency files (PR #86965)

[Matt Arsenault via cfe-commits]

arsenm wrote:

The build here seems to be trying to define clc as a language, which then results in needing to rely on language support magic like this. I think it would be better if this did what rocm-device-libs does and treat these as custom targets. I don't think it's particularly helpful to pretend like this is a normal host compiler detection situation. 

https://github.com/ROCm/llvm-project/blob/efc7219da809b6bce7b1c92c1915a0eac68fb1f2/amd/device-libs/cmake/OCL.cmake#L136

https://github.com/llvm/llvm-project/pull/86965