non-free Packages as build-dependency of contrib / non-free ones & autobuilding
currently our policy says that main packages must only (build-)depend
on main packages, but contrib and non-free packages could use packages
from contrib and non-free.
In practice build-dependencies from non-free are not used by the
buildds for two reasons:
1. (mostly historical) we need to make sure that the packages are not
installed anymore while building packages from main - this can be
ensured via the lvm-snapshot type chroots however
2. we don't know (on an automated basis) which packages in non-free
can be used as build-dependency without violating copyright. For the
source packages we use the marker "Autobuild: yes", but that won't do
for binary packages where we only want to have some packages
considered by apt/aptitude.
Some obvious solutions come to my mind:
1. Split non-free into "non-free-but-useable", i.e. packages that can
be autobuilt, and can be used as a build-dependency (and where main +
contrib + non-free is self-contained, like main today already is), and
"silly-non-free" (the remaining packages).
2. Make a sub-disttree from non-free of the acceptable packages, and
put it somewhere only on ftp-master or a few hosts only (that's enough
for installing build-dependencies on buildds already)
Other ideas? Opinions?