anchor.diff:  { stdenv, substituteAll, fetchurl, fetchpatch
  -, pkgconfig, freetype, expat, libxslt, dejavu_fonts
  +, pkgconfig, freetype, expat, libxslt, gperf, dejavu_fonts
   , hostPlatform
   }:
   
  
positive.code:       src = ./config-compat.patch;
        inherit configVersion;
      })
      (fetchpatch {
        name = "glibc-2.25.diff";
        url = "https://cgit.freedesktop.org/fontconfig/patch/?id=1ab5258f7c";
        sha256 = "0x2a4qx51j3gqcp1kp4lisdzmhrkw1zw0r851d82ksgjlc0vkbaz";
      })
    ];
    # additionally required for the glibc-2.25 patch; avoid requiring gperf
    postPatch = ''
      sed s/CHAR_WIDTH/CHARWIDTH/g -i src/fcobjshash.{h,gperf}
      sleep 2
      touch src/fcobjshash.h
    '';
  
    outputs = [ "bin" "dev" "lib" "out" ]; # $out contains all the config
  
    propagatedBuildInputs = [ freetype ];
    nativeBuildInputs = [ pkgconfig ];
    buildInputs = [ expat ];
  
    configureFlags = [
  
negative.code:   configVersion = "2.11"; # bump whenever fontconfig breaks compatibility with older configurations
  in
  stdenv.mkDerivation rec {
    name = "fontconfig-${version}";
    version = "2.12.6";
  
    src = fetchurl {
      url = "http://fontconfig.org/release/${name}.tar.bz2";
      sha256 = "05zh65zni11kgnhg726gjbrd55swspdvhqbcnj5a5xh8gn03036g";
    };
  
    patches = [
  