Description:
------------
The following code results in a PHP crash with a "zend_mm_heap corrupted" message, either on an UTF-8 environement or ISO-8859-1, with Linux or Windows.

Reproduce code:
---------------
<?php
echo metaphone('CMXFXM');
?>

Actual result:
--------------
KMKSFKSM[Mon Feb 25 17:02:41 2008]  Script:  'test.php'
---------------------------------------
/usr/local/src/php/Zend/zend_variables.h(35) : Block 0xb79dcfb4 status:
/usr/local/src/php/Zend/zend_variables.c(36) : Actual location (location was relayed)
Beginning:      OK (allocated on /usr/local/src/php/ext/standard/metaphone.c:435, 8 bytes)
    Start:      OK
      End:      Overflown (magic=0x00000000 instead of 0xC5FC605D)
                1 byte(s) overflown
---------------------------------------
[Mon Feb 25 17:02:41 2008]  Script:  'test.php'
/usr/local/src/php/ext/standard/metaphone.c(435) :  Freeing 0xB79DCFB4 (8 bytes), script=test.php
=== Total 1 memory leaks detected ===