Description:
------------
Executing

  setlocale(LC_ALL, 'es_ES');          
  $str = "La naci?n es grande";
  $words = split("[^[:alpha:]']+", $str);

words in $str are not recognized as Spanish. For example,
'naci?n' is still split at the '?'.

setlocale returns es_ES indicating the locale was set.


Expected result:
----------------
The original text split into correct words. According to the
regexp docs, [:alpha:] should acquire the Spanish characters
if the locale is set.

Actual result:
--------------
Words are split at non-ASCII characters (??? etc).