Description:
------------
curl_close causes a segfault when accessing a member variable after the call (see code below) when CURLOPT_RETURNTRANSFER is true and CURLOPT_HEADERFUNCTION is set to a member function.

Calling 
curl_setopt($this->curl, CURLOPT_HEADERFUNCTION,array(&$this, 'readHeader'));

again in __destruct (before curl_close) makes the segfault go away.

Adding the line:
zval_copy_ctor(ch->handlers->write_header->func_name);
in ext/curl/interface.c  line 1152 seems to fix it, but I don't know if it produces a memory leak.



Reproduce code:
---------------
<?php

class CurlTest {
	var $curl;
    var $url;

	function readHeader($ch, $data) 
	{
		return strlen($data);
	}

	function __construct($url)
	{		
		$this->curl = curl_init($url);
		curl_setopt($this->curl, CURLOPT_RETURNTRANSFER, true);
		curl_setopt($this->curl, CURLOPT_HEADERFUNCTION, array(&$this, 'readHeader'));
		curl_setopt($this->curl, CURLOPT_URL, $url);
		$this->url = $url;
	}

	function __destruct()
	{
		if (is_resource($this->curl)) {
			curl_close($this->curl);
		}
		$x = $this->url;
	}

	function exec() 
	{
		curl_exec($this->curl);
	}
}


$t = new CurlTest('http://www.google.de');
$t->exec();
$t = null;

?>


Expected result:
----------------
No segfault

Actual result:
--------------
Segfault