To build a binary that will run on the Raspberry Pi, you need to have a Go cross compiler and enable it when building the executable.
To build the cross compiler for Linux/ARM (you only need to do this once):
cd /usr/local/go/src
sudo GOOS=linux GOARCH=arm ./make.bash --no-clean
Once you've done that, you can build a binary for Raspberry Pi:
env GOOS=linux GOARCH=arm go build -o <target_executable> <source_file>
source: http://stackoverflow.com/questions/12168873/cross-compile-go-on-osx