anchor.diff:  
     NIX_CFLAGS_COMPILE = "-fPIC"; # Gentoo adds this on every platform
   
  -  buildInputs = [ pkgconfig flex zlib perl libpng libjpeg libxml2 makeWrapper libX11 libtiff ];
  +  buildInputs =
  +    [ pkgconfig flex zlib perl libpng libjpeg libxml2 makeWrapper libtiff ]
  +    ++ lib.optional enableX11 libX11;
   
     configurePhase = ''
       cp config.mk.in config.mk
  +    echo "STATICLIB_TOO = n" >> config.mk
       substituteInPlace "config.mk" \
           --replace "TIFFLIB = NONE" "TIFFLIB = ${libtiff}/lib/libtiff.so" \
           --replace "TIFFHDR_DIR =" "TIFFHDR_DIR = ${libtiff}/include"
  
positive.code:   enableParallelBuilding = true;
  
    installPhase = ''
      make package pkgdir=$PWD/netpbmpkg
      # Pass answers to the script questions
      ./installnetpbm << EOF
      $PWD/netpbmpkg
      $out
      Y
      $out/bin
      $out/lib
      N
      $out/lib
      $out/lib
      $out/include
      $out/man
      N
      EOF
  
      # wrap any scripts that expect other programs in the package to be in their PATH
      for prog in ppmquant; do
  
negative.code: { lib, stdenv, fetchurl, pkgconfig, libjpeg, libpng, flex, zlib, perl, libxml2
  , makeWrapper, libtiff
  , enableX11 ? false, libX11 }:
  
  stdenv.mkDerivation rec {
    name = "netpbm-10.66.00";
  
    src = fetchurl {
      url = "mirror://gentoo/distfiles/${name}.tar.xz";
      sha256 = "1z33pxdir92m7jlvp5c2q44gxwj7jyf8skiqkr71kgirw4w4zsbz";
    };
  
    postPatch = /* CVE-2005-2471, from Arch */ ''
  