Description:
------------
I'm splitting a string into characters with this:

preg_split('//u', $string, - 1, PREG_SPLIT_NO_EMPTY);


I get a notice on an uknown error which happens when I use the 
unicode suffix u in the pattern and when the input string is 
"\r\n":

$string = chr(13).chr(10);

but not when i drop the unicode option, ie. this works fine:
 
preg_split('//', $string, - 1, PREG_SPLIT_NO_EMPTY);

Reproduce code:
---------------
$string = chr(13).chr(10);

$array = preg_split('//u', $string, - 1, PREG_SPLIT_NO_EMPTY));

print_r(array_map('ord', $array));

Expected result:
----------------
Array
(
    [0] => 13
    [1] => 10
)


Actual result:
--------------
<br />
<b>Notice</b>:  preg_split() [<a href='function.preg-
split'>function.preg-split</a>]: Unknown error in <b>/Users/
myname/Sites/script.php</b> on line <b>73</b><br />
Array
(
    [0] => 13
    [1] => 10
)