copy the entire closure of ‘drvPath’, as well the required

       copy the entire closure of ‘drvPath’, as well as the required

    BasicDerivation basicDrv(step->drv);

            basicDrv.inputSrcs.insert(i->second.path);

        to << cmdBuildDerivation << step->drvPath << step->drv << maxSilentTime << buildTimeout;

        to << cmdBuildDerivation << step->drvPath << basicDrv << maxSilentTime << buildTimeout;