%% -*- mode:erlang -*-
{_, ErlOpts} = lists:keyfind(erl_opts, 1, CONFIG).
Rel = try erlang:system_info(otp_release) of
    Vsn ->
        {match,[Maj]} = re:run(Vsn, "^R?([0-9]+)", [{capture,[1],list}]),
        list_to_integer(Maj)
    catch _:_ ->
        "OLD"
end,
Macros = if Rel < 19 ->
                 [{d, 'OLD_TIME_UNITS'}];
            true ->
                 []
         end,
lists:keystore(erl_opts, 1, CONFIG, {erl_opts, Macros ++ ErlOpts}).