[lld] [llvm] [lld-macho] Implement ObjC category merging (-objc_category_merging) (PR #82928)

[via llvm-commits]

alx32 wrote:

> I think this is causing sanitizer buildbot failures: https://lab.llvm.org/buildbot/#/builders/168/builds/19302/steps/10/logs/stdio

Looking into now. 

https://github.com/llvm/llvm-project/pull/82928