On Ubuntu: from (https://github.com/japaric/rust-cross)
0. Our target is an ARMv7 device, the triple for this target is armv7-unknown-linux-gnueabihf
- sudo apt-get install -qq gcc-arm-linux-gnueabihf
- rustup target add armv7-unknown-linux-gnueabihf
- cargo build --release --target=armv7-unknown-linux-gnueabihf