anchor.diff:  { fetchurl, fetchzip, stdenv, lua, callPackage, unzip, zziplib, pkgconfig, libtool
   , pcre, oniguruma, gnulib, tre, glibc, sqlite, openssl, expat, cairo
   , perl, gtk2, python, glib, gobjectIntrospection, libevent, zlib, autoreconfHook
  -, libmysql, postgresql, cyrus_sasl
  +, mysql, postgresql, cyrus_sasl
   , fetchFromGitHub, libmpack, which
   }:
   
  
positive.code:     };
      sourceRoot = ".";
  
      buildInputs = [ libmysql postgresql sqlite ];
  
      preConfigure = ''
        substituteInPlace Makefile --replace CC=gcc CC=cc
  
negative.code:     '';
  
      NIX_CFLAGS_COMPILE = [
        "-I${mysql.connector-c}/include/mysql"
        "-L${mysql.connector-c}/lib/mysql"
        "-I${postgresql}/include/server"
      ];
  
  