anchor.diff:     for each package in a separate file: the call to the function would
      be almost as must code as the function itself. */
   
  -{ fetchurl, stdenv, lua, callPackage, unzip, zziplib, pkgconfig, libtool
  +{ fetchurl, fetchzip, stdenv, lua, callPackage, unzip, zziplib, pkgconfig, libtool
   , pcre, oniguruma, gnulib, tre, glibc, sqlite, openssl, expat, cairo
   , perl, gtk, python, glib, gobjectIntrospection, libevent, zlib
   }:
  
positive.code:   luazip = buildLuaPackage rec {
      name = "zip-${version}";
      version = "1.2.3";
      src = fetchurl {
        url = "https://github.com/luaforge/luazip/archive/0b8f5c958e170b1b49f05bc267bc0351ad4dfc44.zip";
        sha256 = "beb9260d606fdd5304aa958d95f0d3c20be7ca0a2cff44e7b75281c138a76a50";
      };
      buildInputs = [ unzip zziplib ];
      patches = [ ../development/lua-modules/zip.patch ];
  
negative.code:     name = "luaevent-${version}";
      disabled = isLua52;
  
      src = fetchzip {
        url = "https://github.com/harningt/luaevent/archive/v${version}.tar.gz";
        sha256 = "1c1n2zqx5rwfwkqaq1jj8gvx1vswvbihj2sy445w28icz1xfhpik";
      };
  
      preBuild = ''
  