Rebar config script to set compiler directives. In this example the directive "have_callback_support" will be set as long as an Erlang release with version 15 or higher is available.

module_with_compiler_directive.erl

-module(module_with_compiler_directive).

-ifdef(have_callback_support).

-callback start_link(Args) -> {ok, Pid} |
                              {error, {already_started, Pid}} |
                              {error, Reason} when
    Args   :: proplists:proplist(),
    Pid    :: pid(),
    Reason :: term().

-else.

-export([behaviour_info/1]).

behaviour_info(callbacks) ->
    [{start_link, 1}];
behaviour_info(_Other) ->
    undefined.

-endif.

rebar.config.script

{match, [ErtsNumber]} = re:run(erlang:system_info(otp_release), "R(\\d+).+", [{capture, [1], list}]),
ErtsVsn = erlang:list_to_integer(ErtsNumber),
if
    ErtsVsn >= 15 ->
        OldOpts = proplists:get_value(erl_opts, CONFIG, []),
        NewOpts = [{d, have_callback_support} | OldOpts],
        lists:keystore(erl_opts, 1, CONFIG, {erl_opts, NewOpts});
    true ->
        CONFIG
end.