Revert "No longer need to build binary in go generate so env var GOOS can be whatever is wanted"
Revert "No longer need to build binary in go generate so env var GOOS can be whatever is wanted"

This reverts commit b4644320ee366047fd5a9465a17d7332c3a7443e.

petemoore/taskcluster-client-go,petemoore/taskcluster-client-go,taskcluster/taskcluster-client-go,taskcluster/taskcluster-client-go