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

[Saleem Abdulrasool via llvm-commits]

compnerd wrote:

@yxsamliu - if you are using the runtimes build, the just built compiler can be used to build the runtimes for the hosts that you would like.

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