Description:
------------
Throwing exceptions from within a dynamically called function (via call_user_func or equivalent) causes PHP to segfault.

Reproduce code:
---------------
<pre>
<?php

error_reporting(E_ALL);

class mzTestCase {
	public function run() {
		try {
			call_user_func(array($this, 'runTest'));
		} catch (Exception $e) {
			print "Exception caught ($e)";
		}
	}

	function runTest() {
		print "mseoj\n";
		//SEGFAULTS
		throw new mzTestFailureException();
	}
}

class mzTestFailureException extends Exception {}

$tc = new mzTestCase();
$tc->run();

?>


Expected result:
----------------
Exception caught (the mzTestFailureException details)

Actual result:
--------------
Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 1024 (LWP 674)]
0x4046975a in zend_do_fcall_common_helper (execute_data=0xbfffd050,
    op_array=0x80b37b4) at /root/temp/php-5.0.0b2/Zend/zend_execute.c:2628
2628                    if (EG(exception) && EX(fbc)->common.fn_flags&ZEND_ACC_CTOR) {
(gdb) bt
#0  0x4046975a in zend_do_fcall_common_helper (execute_data=0xbfffd050,
    op_array=0x80b37b4) at /root/temp/php-5.0.0b2/Zend/zend_execute.c:2628
#1  0x40469a77 in zend_do_fcall_handler (execute_data=0xbfffd050,
    op_array=0x80b37b4) at /root/temp/php-5.0.0b2/Zend/zend_execute.c:2696
#2  0x40464e47 in execute (op_array=0x80b37b4)
    at /root/temp/php-5.0.0b2/Zend/zend_execute.c:1271
#3  0x40469409 in zend_do_fcall_common_helper (execute_data=0xbfffd320,
    op_array=0x80b2d50) at /root/temp/php-5.0.0b2/Zend/zend_execute.c:2579
#4  0x40469947 in zend_do_fcall_by_name_handler (execute_data=0xbfffd320,
    op_array=0x80b2d50) at /root/temp/php-5.0.0b2/Zend/zend_execute.c:2665
#5  0x40464e47 in execute (op_array=0x80b2d50)
    at /root/temp/php-5.0.0b2/Zend/zend_execute.c:1271
#6  0x40440ad4 in zend_execute_scripts (type=8, retval=0x0, file_count=3)
    at /root/temp/php-5.0.0b2/Zend/zend.c:1009
#7  0x403f9b2b in php_execute_script (primary_file=0xbffff638)
    at /root/temp/php-5.0.0b2/main/main.c:1622
#8  0x40471d7e in apache_php_module_main (r=0x815c3b4,
    display_source_mode=0)
    at /root/temp/php-5.0.0b2/sapi/apache/sapi_apache.c:54
#9  0x40472e30 in send_php (r=0x815c3b4, display_source_mode=0,
    filename=0x815df4c "/var/www/html/tmp/tests/call_user_func2.php")
    at /root/temp/php-5.0.0b2/sapi/apache/mod_php5.c:621
#10 0x40472eaf in send_parsed_php (r=0x815c3b4)
    at /root/temp/php-5.0.0b2/sapi/apache/mod_php5.c:636
#11 0x08053ab4 in ap_invoke_handler ()
#12 0x0806342c in ap_some_auth_required ()
#13 0x08063488 in ap_process_request ()
#14 0x0805cc6b in ap_child_terminate ()
#15 0x0805cdfc in ap_child_terminate ()
#16 0x0805cf19 in ap_child_terminate ()
#17 0x0805d3f5 in ap_child_terminate ()
#18 0x0805dafd in main ()
#19 0x400f814f in __libc_start_main () from /lib/libc.so.6