ensure Dest exists before copying to it

src/rebar_file_utils.erl

@@ -191,8 +191,8 @@ cp_r(Sources, Dest) ->
         {unix, _} ->
             EscSources = [rebar_utils:escape_chars(Src) || Src <- Sources],
             SourceStr = rebar_string:join(EscSources, " "),
-            {ok, []} = rebar_utils:sh(?FMT("cp -Rp ~ts \"~ts\"",
-                                           [SourceStr, rebar_utils:escape_double_quotes(Dest)]),
+            {ok, []} = rebar_utils:sh(?FMT("mkdir -p \"~ts\" && cp -Rp ~ts $_",
+                                           [rebar_utils:escape_double_quotes(Dest), SourceStr]),
                                       [{use_stdout, false}, abort_on_error]),
             ok;
         {win32, _} ->