[llvm] [ORC-RT] Initial check-in for a new, top-level ORC runtime project. (PR #113499)

[Vassil Vassilev via llvm-commits]

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

This pull request has been under multiple review iterations and I'd like to thank everybody involved. The downstream clients of clang-repl need this and I'd like to move forward because it also blocks a google summer of code contributor of the llvm mentoring org. 

Thank you, @lhames! LGTM.

Perhaps, @llvm-beanz and @petrhosek can take another look maybe as part of a post-commit review if there is something missing.

https://github.com/llvm/llvm-project/pull/113499