lib/erl/rebar.config.script

Def0 = case not erlang:is_builtin(erlang, monotonic_time, 0) of
           true -> [];
           false -> [{d, time_correction}]
       end,
Defs = Def0,
lists:keystore(erl_opts, 1, CONFIG,
               {erl_opts, proplists:get_value(erl_opts, CONFIG, []) ++ Defs}).