anchor.diff:  
   -spec compile(Config::#config{}, AppFile::string()) -> 'ok'.
   compile(Config, _AppFile) ->
  +    rebar_base_compiler:run(Config, rebar_config:get_list(Config, yrl_first_files, []),
  +                            "src", ".yrl", "src", ".erl",
  +                            fun compile_yrl/3),
       doterl_compile(Config, "ebin"),
       rebar_base_compiler:run(Config, rebar_config:get_list(Config, mib_first_files, []),
                               "mibs", ".mib", "priv/mibs", ".bin",
  
positive.code:     %%       the dir structure and delete each file; however it would also
      %%       much slower.
      ok = rebar_file_utils:rm_rf("ebin/*.beam priv/mibs/*.bin"),
  
      %% Erlang compilation is recursive, so it's possible that we have a nested
      %% directory structure in ebin with .beam files within. As such, we want
  
negative.code:             ?FAIL
      end.
  
  -spec compile_yrl(Source::string(), Target::string(), Config::#config{}) -> 'ok'.
  compile_yrl(Source, Target, Config) ->
      case yrl_needs_compile(Source, Target) of
          true ->
              Opts = [{parserfile, Target}, {return, true}
                      |rebar_config:get(Config, yrl_opts, [])],
              case yecc:file(Source, Opts) of
                  {ok, _, []} ->
                      ok;
                  {ok, _, _Warnings} ->
                      case lists:member(fail_on_warnings, Config) of
                          true ->
                              ?FAIL;
                          false ->
                              ok
                      end;
                  _X ->
                      ?FAIL
              end;
          false ->
              skipped
      end.
  
  -spec yrl_needs_compile(Source::string(), Target::string()) -> boolean().
  yrl_needs_compile(Source, Target) ->
      filelib:last_modified(Target) < filelib:last_modified(Source).
  
  gather_src([], Srcs) ->
      Srcs;
  gather_src([Dir|Rest], Srcs) ->
  