Docker `make build` fails

[Shaun]

warning: current architecture ($dpkgArch) does not have a corresponding Go binary release; will be building from source"; echo >&2 ;; esac; url="https://golang.org/dl/go${GOLANG_VERSION}.${goRelArch}.tar.gz"; wget -O go.tgz "$url"; echo "${goRelSha256} *go.tgz" | sha256sum -c -; tar -C /usr/local -xzf go.tgz; rm go.tgz; if [ "$goRelArch" = 'src' ]; then echo >&2; echo >&2 'error: UNIMPLEMENTED'; echo >&2 'TODO install golang-any from jessie-backports for GOROOT_BOOTSTRAP (and uninstall after build)'; echo >&2; exit 1; fi; export PATH="/usr/local/go/bin:$PATH"; go version' returned a non-zero code: 4
Makefile:31: recipe for target 'gocrack' failed
make: *** [gocrack] Error 4