[lld] [lld][MachO]Multi-threaded i/o. Twice as fast linking a large project. (PR #147134)

[David Spickett via llvm-commits]

DavidSpickett wrote:

Great, so I'll expect that to land at some point and keep an eye out for any failures. Just looking at the placement of the `#if`s, I think it will solve the problem.

https://github.com/llvm/llvm-project/pull/147134