lager/rebar.config.script

ExistingErlOpts = proplists:get_value(erl_opts, CONFIG, []),

CONFIG1 = case code:which(persistent_term) of
    preloaded ->
        lists:keyreplace(erl_opts, 1, CONFIG, {erl_opts, [{d, 'HAVE_PERSISTENT_TERM'}|ExistingErlOpts]});
    non_existing ->
        CONFIG
    end,



case erlang:function_exported(rebar3, main, 1) of
    true -> % rebar3
        CONFIG1;
    false -> % rebar 2.x or older
        %% Rebuild deps, possibly including those that have been moved to
        %% profiles
        [{deps, [
	   {goldrush, ".*", {git, "https://github.com/DeadZen/goldrush.git", {tag, "0.1.9"}}}
        ]} | lists:keydelete(deps, 1, CONFIG1)]
end.