NAME
        AndRectRegion -- Perform 2d AND operation of rectangle
                         with region, leaving result in region.
   SYNOPSIS
        AndRectRegion(region,rectangle)
                        a0      a1
        void AndRectRegion( struct region *, struct rectangle * );
   FUNCTION
        Clip away any portion of the region that exists outside
        of the rectangle. Leave the result in region.
   INPUTS
        region - pointer to region structure
        rectangle - pointer to rectangle structure
   NOTES
        Unlike the other rect-region primitives, AndRectRegion() cannot
        fail.
   BUGS
   SEE ALSO
        andregionregion() orrectregion() graphics/regions.h