[C++11] Replace llvm::tie with std::tie.

llvm-svn: 202639
diff --git a/clang/lib/AST/Decl.cpp b/clang/lib/AST/Decl.cpp
index ee9f072..e362c73 100644
--- a/clang/lib/AST/Decl.cpp
+++ b/clang/lib/AST/Decl.cpp
@@ -3429,7 +3429,7 @@
   if (Decls.empty())
     return;
 
-  llvm::tie(FirstDecl, LastDecl) = BuildDeclChain(Decls,
+  std::tie(FirstDecl, LastDecl) = BuildDeclChain(Decls,
                                                  /*FieldsAlreadyLoaded=*/false);
 }