Fix -Walloc-size warning

It's indeed unsafe to treat zend_internal_function as zend_function, because
sizeof(zend_internal_function) < sizeof(zend_function), which can lead to buffer
overflows. This might also be UB.

Either way, this would need to be addressed in the whole codebase.

Author: iluuu1994

Zend/zend_inheritance.c

@@ -97,7 +97,7 @@ static zend_function *zend_duplicate_internal_function(zend_function *func, zend
 	zend_function *new_function;
 
 	if (UNEXPECTED(ce->type & ZEND_INTERNAL_CLASS)) {
-		new_function = pemalloc(sizeof(zend_internal_function), 1);
+		new_function = (zend_function *)pemalloc(sizeof(zend_internal_function), 1);
 		memcpy(new_function, func, sizeof(zend_internal_function));
 	} else {
 		new_function = zend_arena_alloc(&CG(arena), sizeof(zend_internal_function));