That's a good point, thanks.
For comparsion, here's the repo where we keep our builder for OpenJDK: https://github.com/cloudfoundry/java-buildpack-dependency-bu...
I also found: https://github.com/ojdkbuild/ojdkbuild while looking for Red Hat's build scripts. I didn't find those, but only because I am bad at searching. They'll be published somewhere.