Description:
------------
stream_filter_register cause memory leaks when the php version is 5.1.2 and add --enable-debug parameter

Reproduce code:
---------------
<?php
class strtolower_filter extends php_user_filter{}
stream_filter_register("strtolower", "strtolower_filter");
$fp = fopen("foo-bar.txt", "w");
stream_filter_append($fp, "strtolower");
fwrite($fp, "Line1\n");
fwrite($fp, "WORD - 2\n");
fwrite($fp, "Easy As 123\n");
fclose($fp);
readfile("foo-bar.txt");
 ?>


Actual result:
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[Thu Feb 23 13:32:38 2006]  Script:  'stream_filter_register.php'
/home/sqchen/sqchen/php-5.1.2/main/streams/filter.c(78) :  Freeing 0x083EEC14 (32 bytes), script=stream_filter_register.php
Last leak repeated 2 times
=== Total 3 memory leaks detected ===