anchor.diff:          description = "
             This option allows to append lines to nix.conf. 
           ";
  +      };
  +      
  +      extraChrootPaths = mkOption {
  +        default = [];
  +	example = ["/var/dist"];
  +	description = ''
  +	  Extra paths to include in chroot. May be useful if you build
  +	  from private repository mirrors to avoid extra checksumming 
  +	  and copying to store.
  +	'';
         };
   
         distributedBuilds = mkOption {
  
positive.code:           you should increase this value.
          '';
        };
        
      };
    };
  
  
negative.code:                 build-users-group = nixbld
                  build-max-jobs = ${toString (config.nix.maxJobs)}
                  build-use-chroot = ${if config.nix.useChroot then "true" else "false"}
                  build-chroot-dirs = /dev /dev/pts /proc /bin $(echo $extraPaths) ${builtins.toString config.nix.extraChrootPaths}
                  $extraOptions
                  END
                '';
  