Accept an Io\Poll\Handle wherever a stream is taken

[nicolas-grekas]

Needs php/php-src#23810, which exports what an extension needs to recognise a handle.

PHP 8.6 adds Io\Poll\Handle, the object an extension hands out for something that can be waited on. php/frankenphp#2636 is the first to ship them, a background worker and the two sides of a task, and php_poll_handle_get_fd() turns any of them into a descriptor, so php_event_zval_to_fd() takes one next to the streams and sockets it already accepts:

$handle = new FrankenPHP\WorkerHandle();
$event = new Event($base, $handle, Event::READ | Event::PERSIST, function () use ($handle) {
    $handle->tick();
});
$event->add();

The extension builds unchanged on 8.6 otherwise, and make test stays at 28 passed, 0 failed with this.

Opened here because Bitbucket refuses a fork of the upstream repo ("Forking to a different workspace is not allowed") and its issue tracker now answers 410.

[nicolas-grekas]

Let me close: php-src would rather keep the handle API internal to Io\Poll for now (php/php-src#23810), and 8.7 is getting handle types with no descriptor at all, so what an extension should accept has to settle first. Worth revisiting then.