The author should seriously consider factoring out his build scripts and start a crowd-funding campaign to open source it for X thousands of dollars. Hell, I don't even know Rust and I'll donate ten bucks.

The five platforms support is bloody impressive.

The author explains the process briefly here: https://gist.github.com/michaelfairley/d86137085307d2e5c16ee.... I think the most obvious pitfall is the native API calls for both platforms. Maybe a cross platform framework like PhoneGap for Rust?