GGI video driver

To enable the GGI driver, and disable the X driver, run:
./configure --enable-video-ggi --disable-video-x11

Soon I am hoping to make it possible to link more than one driver
at a time, and have them chosen dynamically at runtime.

-Sam Lantinga				(slouken at

Lead Programmer, Loki Entertainment Software–
“Any sufficiently advanced bug is indistinguishable from a feature”
– Rich Kulawiec