javan I have no clue but, remember that this repo is not official, its one person doing bulkbuilds on his own and being kind enough to share the result ;)
In fact, he was asking yesterday about uploading these...
You also may like to know that binaries for 9.0, not RC_2 anymore, are available :)
Also note that, some packages are really fast to build from source ;)
clang,... take several hours to build but, things like
bash will only take a few minutes.