So today I needed to cross compile a basic Golang app from linux/amd64 to linux/arm (for android) on my Ubuntu 14.04 box.
It is actually kinda easy
sudo apt-get install golang-go-linux-arm
because I am running the latest 1.3 golang i needed to run an extra step:
sudo GOARCH=arm ./make.bash
Once you have that setup, it is as simple as:
you@host:~/golang/src/yourrepohost/yourrepos/repo$ GOARCH=arm go build