Description of problem: Some implementations of programming languages and other toolchain components require themselves (possibly through a circular dependence) say to build in the buildsystem. So the suggestion was made to have a bootstrap repository from which the buildsystem can pull such build dependencies when such a new package is added.
ghc and fpc are working round this by using binary bootstrapping fwiw.
Note that this repository was suggested (by Seth) as a way to avoid manually putting binary packages into the buildroot and also avoiding needlessly importing huge bootstrap binaries into the tarball repository that would only be used once.
I think binary bootstrapping or one-offs is going to be the way to handle things like this.