[llvm] [compiler-rt] Pass the CMake binary dir directly (PR #102493)

[Peter Waller via llvm-commits]

https://github.com/peterwaller-arm approved this pull request.

LGTM, I've tested this; discussed on https://github.com/llvm/llvm-project/pull/102475.

https://github.com/llvm/llvm-project/pull/102493