buildpkg doesn't make much sense on some packages like kernel sources, doc packages or binary packages as the .tbz2 is very similar to the original source and compile time is nearly null, but they take up a lot of space (just think of binary games). Therefore I think we need a RESTRICT="nopackage" variable that disables the building of packages. Packages could still be build with ebuild or quickpkg, maybe it's even enough to bypass FEATURES="buildpkg".
Created attachment 21115 [details, diff] patch for emerge
Doesn't make sense from one perspective... but when looking at distributing a binary set of packages that don't require a network connection, it makes a lot of sense. It's a matter of convenience.
spork see #2