[libclc] [libclc] Override generic symbol using llvm-link --override flag instead of using weak linkage (PR #156778)

[Fraser Cormack via cfe-commits]

https://github.com/frasercrmck approved this pull request.

Nice find, thanks.

It might mean it's harder to move away from using LLVM tools (like `llvm-link`) and towards something more like the other runtimes libraries do (using clang), though. I don't know if that's on the roadmap or not.

https://github.com/llvm/llvm-project/pull/156778