[Patch 01/02] mieq threading prep: Only increment tail (push) when the event data is actually in the queue

[Simon Thum]

Jeremy Huddleston wrote:
> -    unsigned int           oldtail = miEventQueue.tail, newtail;
> +    unsigned int           oldtail = miEventQueue.tail;
All fine, but is there a specific reason to remove newtail? Not that I'd
expect this to save more than one or two cycles on any platform...