Severe drop in framerate when running dispwin -X

[gwgill (Graeme W. Gill)]

@betazoid

very mysterious… could someone else edit the code? I did not find new versions of it on github or so.

The only change I notice is that I removed the RROutputPropertyNotifyMask from the XRRSelectInput() mask, since someone reported that this was now causing problems with newer X11 servers (I’d forgotten about that). Perhaps that is what is different.