The question is not whether Android requires aditional software to be useful but whether it can be used with only free software, for otherwise Android-specific projects can't run on a fully free enviroment which is a requirement in GNU Savannah.
A simple approach might be to do what is done for other non-free operating systems, like OS X. Do we host code for projects that only run on those? If no, then we should do the same for Android projects. By the way I, there is the GNU HURD. And Linux, specially in its form of Linux-Libre.
