NAME 
       ClearRegion -- remove all rectangles from region.

   SYNOPSIS 
       ClearRegion(region)
                     a0

        viod ClearRegion( struct region * );

   FUNCTION 
       Clip away all rectangles in the region leaving nothing.

   INPUTS 
       region - pointer to region structure

   BUGS 

   SEE ALSO
        newregion() graphics/regions.h