He probably made it before OpenXcom officially moved to Git.
I also use a stylus with my smartphone so I don't have a big issue with X-Com's interface (plus phones are 320x200 so there's not a whole lot of room for improvement). However, an alternative would be to change the game's input system so, instead of checking which button is exactly under the cursor, it checks which button is *closest* to the cursor (up to a certain distance), therefore allowing a bigger margin of error which comes from "finger pressing".