function liens_cliquables($url){
  $in=array(
  '`((?:https?|ftp)://S+)(s|z)`',
  '`((?<!//)(www.)S+)(s|z)`');
  $out=array(
  '<a href="$1" target="_blank">$1</a>&nbsp;',
  '&nbsp;<a href="http://$1" target="_blank">$1</a>&nbsp;');
  return preg_replace($in,$out,$url);
}