application:start(compiler),
case {erlang:system_info(version), application:get_key(compiler, vsn), os:getenv("JSX_NO_MAPS")} of
    {X, {ok, Y}, false} when X >= "6.0" andalso Y >= "5.0" ->
        CONFIG ++ [{erl_opts, [{d, release_supports_maps}]}];
    _ -> CONFIG
end.