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

[Kyungwoo Lee via llvm-commits]

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@@ -14,15 +14,28 @@
 namespace lld::macho {
 
 namespace objc {
-
+namespace symbol_names {
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kyulee-com wrote:

This change looks good, but which is not directly related.
Can you create a separate PR (NFC) just for this, and the this PR depends on it?

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