message: Work around internal compiler error on GCC 4.8
diff: @@ -332,8 +332,11 @@ public:
  template <class... Us>
  void with(Us&&... xs) {
  + // TODO: replace this workaround with the make_tuple() line when dropping
  + // support for GCC 4.8.
  + std::tuple<typename std::decay<Us>::type...> tmp{std::forward<Us>(xs)...};
  + //auto tmp = std::make_tuple(std::forward<Us>(xs)...);
  // TODO: move tmp into lambda when switching to C++14
  - auto tmp = std::make_tuple(std::forward<Us>(xs)...);
  peek_ = [=] {
  using namespace caf::detail;
  elementwise_compare_inspector<decltype(tmp)> inspector{tmp};
  