[lld] [lld][MachO] Respect dylibs linked with `-allowable_client` (PR #114638)

[Nico Weber via llvm-commits]

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nico wrote:

How big is the .dylib? If it's < 20kB, I suppose having it in the tree until `-allowable_client` support appears is fine. Please do mention the exact command you used to create it in the PR description.

https://github.com/llvm/llvm-project/pull/114638