Casting a huge unsigned value to signed is implementation-defined
behavior in C. By introducing the ZEND_THREEWAY_COMPARE() macro, we
can sidestep this integer overflow/underflow/casting problem.
Previously zend_parse_parameters (and FastZPP) would handle invalid
arguments depending on strict_types: With strict_types=1, a TypeError
is thrown, with strict_types=0 a warning is thrown and (usually) NULL
is returned. Additionally, some functions (constructors always and
other methods sometimes) opt-it to throwing regardless of strict_types.
This commit changes zpp to always generate a TypeError exception in
PHP 8.
