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

[Carlo Cabrera via llvm-commits]

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@@ -407,8 +407,28 @@ static InputFile *addFile(StringRef path, LoadType loadType,
   case file_magic::macho_dynamically_linked_shared_lib_stub:
   case file_magic::tapi_file:
     if (DylibFile *dylibFile =
-            loadDylib(mbref, nullptr, /*isBundleLoader=*/false, isExplicit))
+            loadDylib(mbref, nullptr, /*isBundleLoader=*/false, isExplicit)) {
+      if (isExplicit && !dylibFile->allowableClients.empty()) {
+        bool allowed = std::any_of(
+            dylibFile->allowableClients.begin(),
+            dylibFile->allowableClients.end(), [&](StringRef allowableClient) {
+              // Not what you expect, but exactly as LD64 does.
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carlocab wrote:

Yes, that it does a prefix match. It honestly seems like a bug, but the behaviour has been around for so long that it probably doesn't make sense to change in LD64 anymore.

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