Description:
------------
If an IMAP server closes a connection without sending a BYE command, PHP segfaults on the next IMAP command run on the mailbox resource.  I noticed this while testing against an exchange server, where I was selecting a folder that doesn't exist.  After 10 times it disconnected me without sending a BYE command.  When this happens PHP segfaulted, which doesn't allow for the script to do any error handling.

Reproduce code:
---------------
<?php
//Try testing against an exchange server that disconnects after a //certain number of "bad" commands
$flags = '/novalidate-cert';
$host = 'secure.emailsrvr.com:143';
$username = 'noteworthy2@sts.com';
$password = 'webmail';
$base_imap_string = '{' . $host . $flags . '}';
$connect_string = $base_imap_string . 'INBOX';
$mailbox = imap_open($connect_string, $username, $password, 0, 3);
$connect_string = $base_imap_string . 'Does not exist';
for ($i = 0; $i < 10; $i++) {
    $reopen_success = imap_reopen($mailbox, $connect_string, 0, 3);
}

Expected result:
----------------
imap_reopen either returns false or throws a PHP error.

Actual result:
--------------
The script segfaults.