anchor.diff:          sed -i "$i" -e "s^/bin/pwd^$PWD_P^g"
       done
   
  -    tar xvjf "$srcPorts"
  +    ${if needsPorts then "tar xvjf ${srcPorts}" else ""}
   
       mkdir ../build
       cd ../build
  
positive.code: let
    # For GNU/Hurd, see below.
    version = if hurdHeaders != null then "20100512" else "2.12.1";
  in
  
  assert (cross != null) -> (gccCross != null);
  
negative.code:       sha256 = "01vlr473skl08xpcjz0b4lw23lsnskf5kx9s8nxwa4mwa9f137vm";
      };
  
    # `fetchurl' is a function and thus should not be passed to the
    # `derivation' primitive.
    fetchurl = null;
  