GitHub mirror: https://github.com/TinyCC/tinycc
source: https://help.github.com/articles/about-github-mirrors/
so, basically, it either needs to be a repository you own or you would need to do cron job polling from some third machine.
Or just question why you're doing this to begin with.
The motivation to put up the mirror is that the creator of the original project has no interest in changing his project to work with the languages' package manager, but has endorsed others mirroring it. So I could mirror the original project on Github and add the files needed for the languages' package manager to work with it.