AVIF transcode does not handle XYZ color primaries

[Kaldaien]

lilliput/avif.cpp

Lines 166 to 182 in e0bc154

	if (primaries == AVIF_COLOR_PRIMARIES_BT2020) {
	cv::Matx33f bt2020_to_bt709(
	1.6605f, -0.5876f, -0.0728f, -0.1246f, 1.1329f, -0.0083f, -0.0182f, -0.1006f, 1.1187f);
	cv::transform(tonemapped, converted, bt2020_to_bt709);
	}
	else if (primaries == AVIF_COLOR_PRIMARIES_SMPTE432 ||
	primaries == AVIF_COLOR_PRIMARIES_DCI_P3) {
	cv::Matx33f p3_to_bt709(
	1.2249f, -0.2247f, -0.0002f, -0.0420f, 1.0419f, 0.0001f, -0.0197f, 0.0754f, 0.9443f);
	cv::transform(tonemapped, converted, p3_to_bt709);
	}
	else if (primaries == AVIF_COLOR_PRIMARIES_BT601) {
	cv::Matx33f bt601_to_bt709(
	1.0440f, -0.0440f, 0.0000f, -0.0000f, 1.0000f, 0.0000f, 0.0000f, 0.0000f, 1.0000f);
	cv::transform(tonemapped, converted, bt601_to_bt709);
	}
	else {

There needs to be an additional case here to handle XYZ (i.e.):

constexpr DirectX::XMMATRIX c_fromXYZto709 = // Transposed
{
  {  3.2409698963165283203125f,    -0.96924364566802978515625f,       0.055630080401897430419921875f, 0.0f },
  { -1.53738319873809814453125f,    1.875967502593994140625f,        -0.2039769589900970458984375f,   0.0f },
  { -0.4986107647418975830078125f,  0.0415550582110881805419921875f,  1.05697154998779296875f,        0.0f },
  {  0.0f,                          0.0f,                             0.0f,                           1.0f }
};

xyz_hdr.zip

Attached is a 12-bit HDR image w/ XYZ primaries for testing.