anchor.diff:  
   copy_or_generate_vmargs_file(State, RelName, RelDir) ->
       RelVmargsPath = filename:join([RelDir, "vm.args"]),
  -
       case rlx_state:vm_args(State) of
           undefined ->
  -            ok = file:write_file(RelVmargsPath, vm_args_file(RelName));
  +            unless_exists_write_default(RelVmargsPath, vm_args_file(RelName));
           ArgsPath ->
               case filelib:is_regular(ArgsPath) of
                   false ->
  
positive.code:     rlx_util:to_string(filename:join(filename:dirname(Name),
                                       filename:basename(Name, ".rel"))).
  
  
  get_up_release(State, Release, Vsn) ->
      Name = rlx_release:name(Release),
      try
  
negative.code:     RelSysConfPath = filename:join([RelDir, "sys.config"]),
      case rlx_state:sys_config(State) of
          undefined ->
              unless_exists_write_default(RelSysConfPath, sys_config_file()),
              include_erts(State, Release, OutputDir, RelDir);
          ConfigPath ->
              case filelib:is_regular(ConfigPath) of
  