[compiler-rt] [compiler-rt] Initial support for builtins on GPU targets (PR #95304)

[Yaxun Liu via llvm-commits]

yxsamliu wrote:

> What's the expected way to target multiple architectures in a single build by the way? The logic I see seems to just take the first value from the LLVM default.

By default, the cmake file only build the LLVM default. However for HIP we want to also build the target for device. Since normal users may not want that, we need a LLVM variable to enable it.

https://github.com/llvm/llvm-project/pull/95304