[clang] [OpenMP][AMDGCN] creal/cimag/conj should be builtins/inlined on device. (PR #187831)

[Joseph Huber via cfe-commits]

https://github.com/jhuber6 commented:

I'm not sure this is really true anymore seeing as we have `libc` and `compiler-rt` built for the GPU these days. However, the issue that still remains is that if the backend emits a libcall for a builtin it won't be linked. I still need to think of a proper solution for that.

https://github.com/llvm/llvm-project/pull/187831