Screensaver and blanking prevention doesn't work on Unity

Hi,

I tested on Ubuntu by fullscreening simple.c Screensaver and screen sleep were not prevented.

Looking into the code I see XSetScreenSaver() being called. Apparently it's not very effective. Reviewing other open source projects I see solutions that are a nightmarish mix of xlib, libxss, and dbus freedesktop calls to prevent screensavers and screen sleep. Is there no simple Xlib call that can take care of this?

This issue is related to: https://github.com/glfw/glfw/issues/851