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:   luasqlite3 = buildLuaPackage rec {
      name = "sqlite3-${version}";
      version = "2.1.1";
      src = fetchurl {
        url = "https://github.com/LuaDist/luasql-sqlite3/archive/2acdb6cb256e63e5b5a0ddd72c4639d8c0feb52d.zip";
        sha256 = "1yy1n1l1801j48rlf3bhxpxqfgx46ixrs8jxhhbf7x1hn1j4axlv";
      };
  
      buildInputs = [ unzip sqlite ];
  
negative.code:     name = "zlib-${version}";
      version = "0.4";
  
      src = fetchzip {
        url = "https://github.com/brimworks/lua-zlib/archive/v${version}.tar.gz";
        sha256 = "1pgxnjc0gvk25wsr69nsm60y5ad86z1nlq7mzj3ckygzkgi782dd";
      };
  
      buildInputs = [ zlib ];
  