Update prebuilt Clang to r416183b from Android.

https://android.googlesource.com/platform/prebuilts/clang/host/
linux-x86/+/06a71ddac05c22edb2d10b590e1769b3f8619bef

clang 12.0.5 (based on r416183b) from build 7284624.

Change-Id: I277a316abcf47307562d8b748b84870f31a72866
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/linux-x64/clang/include/clang-tidy/misc/UnusedAliasDeclsCheck.h b/linux-x64/clang/include/clang-tidy/misc/UnusedAliasDeclsCheck.h
new file mode 100644
index 0000000..32e5e15
--- /dev/null
+++ b/linux-x64/clang/include/clang-tidy/misc/UnusedAliasDeclsCheck.h
@@ -0,0 +1,39 @@
+//===--- UnusedAliasDeclsCheck.h - clang-tidy--------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_UNUSED_ALIAS_DECLS_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_UNUSED_ALIAS_DECLS_H
+
+#include "../ClangTidyCheck.h"
+#include "llvm/ADT/DenseMap.h"
+
+namespace clang {
+namespace tidy {
+namespace misc {
+
+/// Finds unused namespace alias declarations.
+class UnusedAliasDeclsCheck : public ClangTidyCheck {
+public:
+  UnusedAliasDeclsCheck(StringRef Name, ClangTidyContext *Context)
+      : ClangTidyCheck(Name, Context) {}
+  bool isLanguageVersionSupported(const LangOptions &LangOpts) const override {
+    return LangOpts.CPlusPlus11;
+  }
+  void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+  void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+  void onEndOfTranslationUnit() override;
+
+private:
+  llvm::DenseMap<const NamedDecl *, CharSourceRange> FoundDecls;
+};
+
+} // namespace misc
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_UNUSED_ALIAS_DECLS_H