Try to make VS 2012 happy after r217155

It was failing with:

C:\bb-win7\ninja-clang-i686-msc17-R\llvm-project\llvm\include\llvm/Support/ErrorOr.h(102) : error C3861: 'make_error_code': identifier not found

        C:\bb-win7\ninja-clang-i686-msc17-R\llvm-project\clang-tools-extra\clang-tidy\ClangTidyOptions.cpp(153) : see reference to function template instantiation 'llvm::ErrorOr<T>::ErrorOr<std::errc::errc>(E,void *)' being compiled

        with
        [
            T=clang::tidy::ClangTidyOptions,
            E=std::errc::errc
        ]