message: fix initializer list copy warnings
diff: @@ -680,14 +680,14 @@ namespace detail {
  template <typename T>
  -std::initializer_list<std::initializer_list<T>> l(
  - std::initializer_list<std::initializer_list<T>> list)
  +const std::initializer_list<std::initializer_list<T>> &l(
  + const std::initializer_list<std::initializer_list<T>> &list)
  {
  return list;
  }
  template <typename T>
  -std::initializer_list<T> l(std::initializer_list<T> list)
  +const std::initializer_list<T> &l(const std::initializer_list<T> &list)
  {
  return list;
  }
  @@ -711,7 +711,20 @@ T *plain_ptr(const std::unique_ptr<T> &ptr)
  }
  template <typename T>
  -T plain_ptr(T ptr)
  +const std::initializer_list<T> &plain_ptr(const std::initializer_list<T> &ptr)
  +{
  + return ptr;
  +}
  +
  +template <typename T>
  +const std::initializer_list<std::initializer_list<T>> &plain_ptr(
  + const std::initializer_list<std::initializer_list<T>> &ptr)
  +{
  + return ptr;
  +}
  +
  +template <typename T>
  +T *plain_ptr(T *ptr)
  {
  return ptr;
  }
  