Silence gcc 5.1 unused variable warnings using LLVM_ATTRIBUTE_UNUSED.

llvm-svn: 244329
diff --git a/clang-tools-extra/clang-tidy/tool/ClangTidyMain.cpp b/clang-tools-extra/clang-tidy/tool/ClangTidyMain.cpp
index 075df04..a6d5e8b 100644
--- a/clang-tools-extra/clang-tidy/tool/ClangTidyMain.cpp
+++ b/clang-tools-extra/clang-tidy/tool/ClangTidyMain.cpp
@@ -336,19 +336,19 @@
 
 // This anchor is used to force the linker to link the LLVMModule.
 extern volatile int LLVMModuleAnchorSource;
-static int LLVMModuleAnchorDestination = LLVMModuleAnchorSource;
+static int LLVM_ATTRIBUTE_UNUSED LLVMModuleAnchorDestination = LLVMModuleAnchorSource;
 
 // This anchor is used to force the linker to link the GoogleModule.
 extern volatile int GoogleModuleAnchorSource;
-static int GoogleModuleAnchorDestination = GoogleModuleAnchorSource;
+static int LLVM_ATTRIBUTE_UNUSED GoogleModuleAnchorDestination = GoogleModuleAnchorSource;
 
 // This anchor is used to force the linker to link the MiscModule.
 extern volatile int MiscModuleAnchorSource;
-static int MiscModuleAnchorDestination = MiscModuleAnchorSource;
+static int LLVM_ATTRIBUTE_UNUSED MiscModuleAnchorDestination = MiscModuleAnchorSource;
 
 // This anchor is used to force the linker to link the ReadabilityModule.
 extern volatile int ReadabilityModuleAnchorSource;
-static int ReadabilityModuleAnchorDestination = ReadabilityModuleAnchorSource;
+static int LLVM_ATTRIBUTE_UNUSED ReadabilityModuleAnchorDestination = ReadabilityModuleAnchorSource;
 
 } // namespace tidy
 } // namespace clang