anchor.diff: -{ stdenv, fetchurl, pkgconfig, freetype, expat, libxslt, fontbhttf }:
  +{ stdenv, fetchurl, fetchpatch, pkgconfig, freetype, expat, libxslt, fontbhttf }:
   
   let
     configVersion = "2.11"; # bump whenever fontconfig breaks compatibility with older configurations
  
positive.code:         sha256 = "1fm5xx0mx2243jrq5rxk4v0ajw2nawpj23399h710bx6hd1rviq7";
        }
      ;
  
    propagatedBuildInputs = [ freetype ];
    buildInputs = [ pkgconfig libxslt expat ];
  
negative.code:   passthru = {
      inherit configVersion;
    };
  
    meta = with stdenv.lib; {
      description = "A library for font customization and configuration";
      homepage = http://fontconfig.org/;
  