Today's horrible computer discovery: Github will not let you create a pull request from repo A to repo B unless there is specifically a fork relationship in github.com's database from repo A to repo B. It doesn't help for the git commits to simply be all the same. If there is a way to create this fork relationship after the fact I couldn't find one, so I wound up renaming a github repo to move it out of the way, then forking a new one, then rerunning the git push
