Fix compilation errors.

Hi,

The demo should now compile on Linux and on FreeBSD.

I compiled it an ran it on FreeBSD 9.0, Ubuntu 10.04 and Arch. Some pieces of code are missing, like specialization functions for 8 bit CPU and platform specific main loops.

Only on Arch I could see zoomed images. FreeBSD doesn't show them, and Ubuntu 10.04 doesn't draw anything on the screen. Also, the audio stuttering/delay is toned down on Ubuntu, so the drum track really stands out, destroying the abstract feel of the demo. I'm working on these issues.