Function byteswap_32

app/src/ThirdParty/fast_float.h:1718–1721

}

fastfloat_really_inline constexpr uint32_t byteswap_32(uint32_t val) {
  return (val >> 24) | ((val >> 8) & 0x0000FF00u) | ((val << 8) & 0x00FF0000u) |
         (val << 24);
}

// Read 8 UC into a u64. Truncates UC if not char.
template <typename UC>