[clang] [CIR] Upstream global variable linkage types (PR #129072)

[Andy Kaylor via cfe-commits]

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@@ -36,6 +36,10 @@ struct MissingFeatures {
   static bool opGlobalConstant() { return false; }
   static bool opGlobalAlignment() { return false; }
   static bool opGlobalLinkage() { return false; }
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andykaylor wrote:

Can this be removed now?

https://github.com/llvm/llvm-project/pull/129072