sub compile { local $^W; 
  # try regexp as it should be, apply patch if doesn't work
  foreach (regexp(), regexp('??')) {
    eval qq{sub parse_re { use re "eval"; 1 while \$_[0] =~ m{$_}go }; 1} or die;
    last if eval { parse_re('<foo>bar</foo>'); 1 }
  };

  *compile = sub {};
}