Description:
------------
After upgrading from 4.3.1 to 4.3.3 the mail-function swallows every 1004th character you try to send.

When switching back to 4.3.1 everything works fine again.

This could be a side-effect of the socket-problems in 4.3.3 .

Reproduce code:
---------------
<?php
$body = "";
for ($i=0;$i<100;$i++) {
$body .= "0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789
";
}	
mail( "someone@test.com", "Test", $body, "" );
?>


Expected result:
----------------
I expect to receive an email with 100 lines and 100 chars in each line.


Actual result:
--------------
What I get is a single missing character every 10 lines.