Neither Android nor Apple color fonts render correctly under Linux in QML

With both the native font rendering method and the Qt renderer under Linux colour fonts (such as Emoji One) fail to display correctly. As I understand it this functionality works to some extent on other platforms (e.g. Apple fonts render on MacOS X via the native renderer).

This can be reproduced with the attached QML and the Emoji One fonts from: https://github.com/Ranks/emojione/tree/master/assets/fonts