Is a micron the name of the straight line over the 'a' in Māori? A single pixel line over a bunch of a's is tremendously simple to do in pixel fonts, I could probably add that to all the fonts in a day... hmmmm
In Māori, there are ā, ē, ī, ō and ū.
Together with the macron, pinyin (the main romanization for Chinese) would be mostly supported. https://en.wikipedia.org/wiki/Pinyin