[Nix-dev] Zero Hydra Failures (ZHF) project

[Michael Raskin]

>> hydraPlatforms is a reasonable solution for another problem; when the
>> build takes more space than time
>
>When a build takes more space/bandwidth than time, I'd expect 
>preferLocalBuild = true; instead of setting hydraPlatforms.

preferLocalBuild is to save hassle for local machines; hydraPlatforms 
is to prevent the hassle for Hydra, too.