message: Avoid triggering GCC4.9 nastiness with the reverse_view<reverse_view> specialization
diff: @@ -109,6 +109,7 @@ namespace ranges
  }
  };
  +#if !defined(__GNUC__) || defined(__clang__) || __GNUC__ >= 5
  template<typename Rng>
  struct reverse_view<reverse_view<Rng>>
  : identity_adaptor<Rng>
  @@ -120,6 +121,7 @@ namespace ranges
  : identity_adaptor<Rng>(rng.base())
  {}
  };
  +#endif // !GCC4
  namespace view
  {
  