anchor.diff: -{ stdenv, fetchurl, fetchgit, pkgconfig, cmake, libiconvOrEmpty, libintlOrEmpty
  +{ stdenv, fetchurl, fetchpatch, pkgconfig, cmake, libiconvOrEmpty, libintlOrEmpty
   , zlib, curl, cairo, freetype, fontconfig, lcms, libjpeg, openjpeg
   , qt4Support ? false, qt4 ? null
   }:
  
positive.code: let
    version = "0.28.1"; # even major numbers are stable
    sha256 = "01pxjdbhvpxf00ncf8d9wxc8gkcqcxz59lwrpa151ah988inxkrc";
  
    poppler_drv = nameSuff: merge: stdenv.mkDerivation (stdenv.lib.mergeAttrsByFuncDefaultsClean [
    rec {
  
negative.code:   poppler_glib = poppler_drv "glib" { };
  
    poppler_qt4 = poppler_drv "qt4" {
      patches = [ qtcairo_patch ];
      propagatedBuildInputs = [ qt4 poppler_glib ];
      NIX_LDFLAGS = "-lpoppler";
      postConfigure = ''
  