anchor.diff:  -export_type([header/0, header_name/0, header_value/0]).
   -export_type([scheme/0, code/0]).
   
  --export([get_env/2, get_env/3]).
  +-export([get_env/2, get_env/3, get_env/4]).
   
   -include("nklib.hrl").
   
  
positive.code: %% ===================================================================
  
  
  %% @doc Equivalent to get_env(App, Key, undefined)
  -spec get_env(atom(), term()) ->
  	term().
  
  get_env(App, Key) ->
      get_env(App, Key, undefined).
  
  
  %% @doc Gets a environment value from the applications config values,
  %% the init line or a OS environment.
  -spec get_env(atom(), term(), term()) ->
  	term().
  
  get_env(App, Key, Default) ->
      case application:get_env(App, Key) of
          {ok, Val} -> 
              Val; 
  
negative.code:                 {ok, [[Val]]} -> 
                      list_to_binary(Val);
                  _ ->
                      EnvKey = Header ++ "_" ++ 
                               string:to_upper(nklib_util:to_list(Key)),
                      case os:getenv(EnvKey) of
                          false -> Default;
  