[AD] window resizing

[Jon Rafkind <workmin@xxxxxxxxxx>]

I have hacked on xwin.c to enable window resizing in X11 which works 
fine but I have not found a clean way yet to update the graphics driver 
and the current screen bitmap. Im not familiar enough with the Allegro 
internals to know of a good way to do this. Would a callback work? The 
way I imagine it is when the ConfigureNotify event is received in the X 
event handler, it calls a function pointer much like what 
_xwin_mouse_interrupt is, to reconfigure the gfx driver and update the 
screen bitmap. It would also call a user supplied call back( if one is 
set ) to let the user update their own stuff.

The xwin code doesnt seem to "know" about the current graphics driver, 
though, except for the times that it is passed into a function such as 
_xwin_create_screen. Is there some way to get the current gfx driver?