Declarations for all the functions. Do I really need a header file? 

Better bounds checking on the few args that don't have it.

All the bits to do transparency via overlays are there, but I have
no idea if it works at all. Anyone with an SGI box want to get
it working?

Fix the flicker problems. I'm effectively using double buffering by copying
from the text pixmap; the main cause of flicker now seems to be related 
to creating the window in the first place.

