anchor.diff:  
     buildInputs = [
       acl
  +    attr
       gpm
       ncurses
     ];
  
positive.code:   inherit (lib)
      optionalString;
  
    version = "8.1.0944";
  in
  stdenv.mkDerivation rec {
    name = "vim-${version}";
  
negative.code: , lib
  
  , acl
  , attr
  , gpm
  , ncurses
  
  