anchor.diff:  , getopt
   }:
   
  -assert enableMySQLDatabase -> mysql != null;
  +assert enableMySQLDatabase -> mariadb != null;
   assert enablePostgreSQLDatabase -> postgresql != null;
   assert enableSubversionRepository -> subversion != null;
   assert enableEjabberdDump -> ejabberd != null;
  
positive.code:   buildInputs = [ getopt netcat ]
      ++ lib.optional stdenv.isLinux systemd
      ++ lib.optional enableEjabberdDump ejabberd
      ++ lib.optional enableMySQLDatabase mysql.out
      ++ lib.optional enablePostgreSQLDatabase postgresql
      ++ lib.optional enableSubversionRepository subversion
      ++ lib.optionals enableMongoDatabase [ mongodb mongodb-tools ]
  
negative.code: { lib, stdenv, fetchurl, netcat
  
  # Optional packages
  , systemd ? null, ejabberd ? null, mariadb ? null, postgresql ? null, subversion ? null
  , mongodb ? null, mongodb-tools ? null, influxdb ? null, supervisor ? null, docker ? null
  , nginx ? null, s6-rc ? null, xinetd ? null
  
  