rebar.config.script

case erlang:system_info(otp_release) =< "R15B01" of
    true  ->
        HashDefine = [{d,old_hash}],
        case lists:keysearch(erl_opts, 1, CONFIG) of
            {value, {erl_opts, Opts}} ->
                lists:keyreplace(erl_opts,1,CONFIG,{erl_opts,Opts++HashDefine});
            false ->
                CONFIG ++ [{erl_opts, HashDefine}]
        end;
    false -> CONFIG
end.