[Nix-dev] Hydra impurity reminder

[Yury G. Kudryashov]

Hi!

I think that it would be nice if hydra will send output of `grep -ir /usr 
$buildDir` to the maintainers to remind about impure paths. What do you 
think about it?

Another nice feature would be sending the output of the configure phase. I 
see that sometimes nix people upgrade packages without local rebuilds (e.g., 
"big fat KDE upgrade"). Sometimes a package fails to find an optional 
dependency, and nobody notices this untill someone needs the feature.

P.S.: I've just found a few impure paths in kdesdk. I'll try to fix it and 
send merge-request upstream.