[compiler-rt] [tsan] Fix running check-ubsan with COMPILER_RT_DEBUG=ON (PR #83890)

[Fangrui Song via llvm-commits]

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@@ -212,8 +212,8 @@ struct InternalDeadlockDetector {
     return initialized > 0;
   }
 };
-
-static THREADLOCAL InternalDeadlockDetector deadlock_detector;
+__attribute__((tls_model("initial-exec"))) static THREADLOCAL
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MaskRay wrote:

This deserves a comment.

https://github.com/llvm/llvm-project/pull/83890