[clang] [CMake][Release] Use llvm-bitcode-strip on Darwin for build with -ffat-lto-objects (PR #200764)

[Tobias Hieta via cfe-commits]

tru wrote:

long term it would be neat if llvm-strip could handle both of these instead of having to select the "correct" version of the strip command?

https://github.com/llvm/llvm-project/pull/200764