message: Fix icon decoding on X11
  Glutin is waiting for an RGBA buffer with 8-bit depth, but our icon is
  16-bit depth. So we need to normalize the color data when decoding the
  icon.
diff: @@ -324,11 +324,13 @@ impl Window {
  pub fn get_platform_window(identity: &Identity, window_config: &WindowConfig) -> WindowBuilder {
  #[cfg(feature = "x11")]
  let icon = {
  - let decoder = Decoder::new(Cursor::new(WINDOW_ICON));
  + let mut decoder = Decoder::new(Cursor::new(WINDOW_ICON));
  + decoder.set_transformations(png::Transformations::normalize_to_color8());
  let mut reader = decoder.read_info().expect("invalid embedded icon");
  let mut buf = vec![0; reader.output_buffer_size()];
  let _ = reader.next_frame(&mut buf);
  Icon::from_rgba(buf, reader.info().width, reader.info().height)
  + .expect("invalid embedded icon format")
  };
  let builder = WindowBuilder::new()
  @@ -341,7 +343,7 @@ impl Window {
  .with_fullscreen(window_config.fullscreen());
  #[cfg(feature = "x11")]
  - let builder = builder.with_window_icon(icon.ok());
  + let builder = builder.with_window_icon(Some(icon));
  #[cfg(feature = "x11")]
  let builder = match window_config.decorations_theme_variant() {
  