libcamera: event_dispatcher_poll: Handle interrupted ppoll() calls

The ppoll() call can be interrupted if a signal is delivered. Handle the
EINTR error code gracefully by restarting the call. This fixes the
event-dispatcher test failure.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>

src/libcamera/include/event_dispatcher_poll.h

@@ -41,6 +41,7 @@ private:
 	std::map<int, EventNotifierSetPoll> notifiers_;
 	std::list<Timer *> timers_;
 
+	int poll(std::vector<struct pollfd> *pollfds);
 	void processNotifiers(const std::vector<struct pollfd> &pollfds);
 	void processTimers();
 };