Description:
------------
Throwing an exception from inside a catch block within an exception handler function causes a fatal error.

If I comment out the marked line, the fatal error does not occur.

I would expect PHP to re-call the master exception handler function.

Reproduce code:
---------------
class TestException extends Exception { }
set_exception_handler('handler');

function handler($ex)
{	
	/* Just to rule out recursion */
	if ($ex instanceof TestException) {	die("Recursion"); }	
	try 
	{		
		/* This is where I would attempt to write to the db */
		throw new Exception("someDBFunction failed");				
	}
	catch (Exception $ex)
	{	
		/* If I comment out the following line, the error goes away */
		throw new TestException("The db logging function failed..write to file.");		
	}	
}
throw new Exception("Ex");

Expected result:
----------------
The script should die with the message "Recursion"

Actual result:
--------------
Fatal error: Exception thrown without a stack frame in Unknown on line 0