Allow for three expression types to be sent to functions which are requesting
the function argument to be passed by reference (only c. was previously
supported):
a. func(new myclass());
b. func(func2()); where func2() returns a reference, i.e. is defined as
function &func2(...)
{
...
}
c. func($var); where func() is defined as function func(&$var) {...}
You CAN'T count on any other expressions to be passable by reference.
(Andi, Zend Engine)