remove use of 17+ function lists:droplast/1

src/rebar_app_discover.erl

@@ -102,7 +102,7 @@ find_app(AppDir, Validate) ->
     end.
 
 app_dir(AppFile) ->
-    filename:join(lists:droplast(filename:split(filename:dirname(AppFile)))).
+    filename:join(rebar_utils:droplast(filename:split(filename:dirname(AppFile)))).
 
 create_app_info(AppDir, AppFile) ->
     case file:consult(AppFile) of

src/rebar_app_utils.erl

@@ -75,7 +75,7 @@ is_app_src(Filename) ->
     Filename =/= filename:rootname(Filename, ".app.src").
 
 app_src_to_app(Filename) ->
-    Path = filename:join(lists:droplast(filename:split(filename:dirname(Filename)))),
+    Path = filename:join(rebar_utils:droplast(filename:split(filename:dirname(Filename)))),
     AppFile = filename:join([Path, "ebin", filename:basename(Filename, ".app.src") ++ ".app"]),
     filelib:ensure_dir(AppFile),
     AppFile.

src/rebar_erlc_compiler.erl

@@ -397,7 +397,7 @@ u_add_element(Elem, [])           -> [Elem].
                    rebar_state:t()) -> [file:filename(), ...].
 include_path(Source, Config) ->
     ErlOpts = rebar_state:get(Config, erl_opts, []),
-    Dir = filename:join(lists:droplast(filename:split(filename:dirname(Source)))),
+    Dir = filename:join(rebar_utils:droplast(filename:split(filename:dirname(Source)))),
     lists:usort([filename:join(Dir, "include"), filename:dirname(Source)]
                 ++ proplists:get_all_values(i, ErlOpts)).
 

src/rebar_utils.erl

@@ -26,7 +26,8 @@
 %% -------------------------------------------------------------------
 -module(rebar_utils).
 
--export([get_cwd/0,
+-export([droplast/1,
+         get_cwd/0,
          is_arch/1,
          get_arch/0,
          wordsize/0,
@@ -77,6 +78,9 @@
 %% Public API
 %% ====================================================================
 
+droplast(L) ->
+    lists:reverse(tl(lists:reverse(L))).
+
 get_cwd() ->
     {ok, Dir} = file:get_cwd(),
     Dir.