Comment 15 for bug 1560498

I *think* it looks like there's something similar going on inside QtMir (http://bazaar.launchpad.net/~mir-team/qtmir/trunk/view/head:/src/platforms/mirserver/screen.cpp#L60):

enum QImage::Format qImageFormatFromMirPixelFormat(MirPixelFormat mirPixelFormat) {
    switch (mirPixelFormat) {
    case mir_pixel_format_abgr_8888:
        if (isLittleEndian()) {
            // 0xRR,0xGG,0xBB,0xAA
            return QImage::Format_RGBA8888;
        } else {
            // 0xAA,0xBB,0xGG,0xRR
            qFatal("[mirserver QPA] "
                   "Qt doesn't support mir_pixel_format_abgr_8888 in a big endian architecture");
        }
        break;
    case mir_pixel_format_xbgr_8888:
        if (isLittleEndian()) {
            // 0xRR,0xGG,0xBB,0xXX
            return QImage::Format_RGBX8888;
        } else {
            // 0xXX,0xBB,0xGG,0xRR
            qFatal("[mirserver QPA] "
                   "Qt doesn't support mir_pixel_format_xbgr_8888 in a big endian architecture");
        }
        break;
        break;
    case mir_pixel_format_argb_8888:
        // 0xAARRGGBB
        return QImage::Format_ARGB32;
        break;
    case mir_pixel_format_xrgb_8888:
        // 0xffRRGGBB
        return QImage::Format_RGB32;
        break;
    case mir_pixel_format_bgr_888:
        qFatal("[mirserver QPA] Qt doesn't support mir_pixel_format_bgr_888");
        break;
    default:
        qFatal("[mirserver QPA] Unknown mir pixel format");
        break;
    }
    return QImage::Format_Invalid;
}