Before going to a last resort of drilling it, you should try a rubber band in between the screw and manual screwdriver. The screwdriver should be a little bit bigger than the one that stripped the screw, and you will need to apply quite a bit of force for this to work. Just be careful so you don't break anything while trying this.
If you get it out far enough, pliers will be able to get it out the rest of the way.