[lld] [lld][MachO] Support for -interposable (PR #131813)

[John Holdsworth via llvm-commits]

johnno1962 wrote:

HI Folks, how about landing this PR before it collects any conflicts? It's a very limited change to unlock a latent capability of your code and as such possess very limited risk of causing a collateral regression. Interposing is an very useful thing for a linker to be able to do which I use in the project [InjectionIII](https://github.com/johnno1962/InjectionIII) which is [motivated here](https://forums.swift.org/t/weve-been-doing-it-wrong-all-this-time/72015). I'm interested in ldd as it has started turning up in Apple's daily build of their developer toolchain so it looks like they are evaluating it. It would be a shame if it were to not include the -interposable option given how easily it could.

https://github.com/llvm/llvm-project/pull/131813