[llvm] cmake: Try to derive CMAKE_SYSTEM_NAME from unnormalized triples (PR #208496)

[Matt Arsenault via llvm-commits]

arsenm wrote:

> Have you explored alternative approaches that wouldn't require parsing target triples in CMake?

I don't know what that could possibly be. Ideally there would be a tool that gives you the system name from the triple that uses the TargetParser code. But that would still have the same fundamental problem as using clang, which is you need to first build a binary you can execute 



https://github.com/llvm/llvm-project/pull/208496