[llvm-branch-commits] [compiler-rt] release/19.x: Forward declare OSSpinLockLock on MacOS since it's not shipped on the system. (#101392) (PR #101432)

[Tim Northover via llvm-branch-commits]

TNorthover wrote:

Looks safe enough to me. The added declaration matches the one in the header. I don't think it's actually gone yet in the latest Xcode 16 beta public SDK, but presumably it's happening soon.

https://github.com/llvm/llvm-project/pull/101432