Fix PHP 8.x compatibility

[manusfreedom]

xml_parser_create no longer returns a resource but a opaque class XMLParser.

Xmlrpcs.php must be corrected as well.

[gxgpet]

Sounds good, only that spl_object_id() isn't compatible with all the PHP versions we are supporting. We will have to use something else.

I will try to come up with a suggestion or an implementation in the following days.

[marios88]

@gxgpet you can have a look at

https://github.com/symfony/polyfill-php72/blob/70f4aebd92afca2f865444d30a4d2151c13c3179/Php72.php#L89

for an implementation

[madwings]

@gxgpet anything new on this?

[gxgpet]

Hi! Please check #6264 and let me know there if it doesn't work for you.