[lld] [LLD][COFF] Allow -arm64xsameaddress in ARM64EC directives (PR #139631)

[Jacek Caban via llvm-commits]

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@@ -31,6 +31,9 @@ multiclass B_priv<string name> {
 def align   : P<"align", "Section alignment">;
 def aligncomm : P<"aligncomm", "Set common symbol alignment">;
 def alternatename : P<"alternatename", "Define weak alias">;
+def arm64xsameaddress
+    : P<"arm64xsameaddress", "Generate a thunk for the symbol with the same "
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cjacek wrote:

Yes, I have a draft of it, but I still need to work out a few details and finish it. I noticed that for other no-op options we use `P_priv`, so I switched to that with the intention of updating it alongside the actual implementation. Thanks!

https://github.com/llvm/llvm-project/pull/139631