anchor.diff: -{ lib, stdenv, fetchurl, fetchpatch, libxml2, findXMLCatalogs, gettext, python3, libgcrypt
  +{ lib, stdenv, fetchurl
  +, pkg-config
  +, libxml2, findXMLCatalogs, gettext, python3, libgcrypt
   , cryptoSupport ? false
   , pythonSupport ? stdenv.buildPlatform == stdenv.hostPlatform
   }:
  
positive.code: 
    outputs = [ "bin" "dev" "out" "man" "doc" ] ++ lib.optional pythonSupport "py";
  
    buildInputs = [ libxml2.dev ]
      ++ lib.optional stdenv.isDarwin gettext
      ++ lib.optionals pythonSupport [ libxml2.py python3 ]
  
negative.code:   propagatedBuildInputs = [ findXMLCatalogs ];
  
    configureFlags = [
      "--without-debug"
      "--without-mem-debug"
      "--without-debugger"
  