anchor.diff: -{ stdenv, fetchurl, nettools, iputils, iproute, makeWrapper, coreutils, gnused }:
  +{ stdenv, fetchurl, perl, file, nettools, iputils, iproute, makeWrapper, coreutils, gnused }:
   
   stdenv.mkDerivation rec {
  -  name = "dhcp-4.1-ESV-R6";
  +  name = "dhcp-${version}";
  +  version = "4.3.0";
     
     src = fetchurl {
  -    url = http://ftp.isc.org/isc/dhcp/4.1-ESV-R6/dhcp-4.1-ESV-R6.tar.gz;
  -    sha256 = "17md1vml07szl9dx4875gfg4sgnb3z73glpbq1si7p82mfhnddny";
  +    url = "http://ftp.isc.org/isc/dhcp/${version}/${name}.tar.gz";
  +    sha256 = "12mydvj6x3zcl3gla06bywfkkrgg03g66fijs94mwb7kbiym3dm7";
     };
   
     patches =
  
positive.code:   # Fixes "socket.c:591: error: invalid application of 'sizeof' to
    # incomplete type 'struct in6_pktinfo'".  See
    # http://www.mail-archive.com/blfs-book@linuxfromscratch.org/msg13013.html
    NIX_CFLAGS_COMPILE = "-D_GNU_SOURCE";
  
    # It would automatically add -Werror, which disables build in gcc 4.4
    # due to an uninitialized variable.
    CFLAGS = "-g -O2 -Wall";
  
    buildInputs = [ makeWrapper ];
  
    postInstall =
      ''
  
negative.code: 
    preConfigure =
      ''
        substituteInPlace configure --replace "/usr/bin/file" "${file}/bin/file"
        sed -i "includes/dhcpd.h" \
  	-"es|^ *#define \+_PATH_DHCLIENT_SCRIPT.*$|#define _PATH_DHCLIENT_SCRIPT \"$out/sbin/dhclient-script\"|g"
      '';
  