[compiler-rt] [CMake] [compiler-rt] fix architecture checks in runtime builds (PR #66374)

[Chris B via llvm-commits]

llvm-beanz wrote:

This is effectively the same problem that the `test_compile_only` macro was added to solve. There are a bunch of cases in compiler-rt where you can only verify that the compile works not the compile+link.

Can you share more about your configuration that’s leading you to this failure?

CMake has changed and evolved _a lot_ since I wrote a lot of the hacky mess that drives this all, so some of these decisions should probably be revisited.

https://github.com/llvm/llvm-project/pull/66374