Ship */runtime/cgo.a in golang-go to ensure it is present. It can only be used on the native architecture anyway (cannot be used when cross-compiling), so having it in golang-go-$GOOS-$GOARCH is not necessary. Even worse, since these packages are arch: all, they will be built precisely once, and only the runtime/cgo.a for the buildd’s native arch will be present. (Closes: #715025)