message: Forward declare `memcpy_cast` in fwd.h
diff: @@ -293,6 +293,8 @@ struct Packet;
  template <typename Value, size_t Size, bool Approx = false, RoundingMode Mode = RoundingMode::Default> struct Mask;
  template <typename Value, size_t Size, bool Approx = false, RoundingMode Mode = RoundingMode::Default> struct PacketMask;
  +template<typename T, typename U> T memcpy_cast(const U &);
  +
  //! @}
  // -----------------------------------------------------------------------
  