[clang] [clang] Extend -Wunused-but-set-variable to static globals (PR #178342)

[Yanzuo Liu via cfe-commits]

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@@ -141,6 +141,9 @@ Attribute Changes in Clang
 
 Improvements to Clang's diagnostics
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+- ``-Wunused-but-set-variable`` now diagnoses file-scope variables with
+  internal linkage (``static`` storage class) that are assigned but never used.
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zwuis wrote:

Reference the issue fixed by this PR like other entries.

https://github.com/llvm/llvm-project/pull/178342