NAME
	AreaCircle -- add a circle to areainfo list for areafill.


    SYNOPSIS
	error = (int) AreaCircle( rp,  cx,  cy, radius)
	D0			  A1   D0   D1	D2

	 ULONG AreaCircle(struct  RastPort *,  WORD,  WORD,  UWORD);

    FUNCTION
	Add circle to the vector buffer. It will be drawn to the rastport when
	 AreaEnd is executed.

    INPUTS
	rp	 - pointer to a  RastPort structure

	cx, cy   - the coordinates of the center of the desired circle.

	radius	 - is the radius of the circle to draw around the centerpoint.

    RESULTS
	0 if no error
	-1 if no space left in vector list

    NOTES
	This function is actually a macro which calls 
	     AreaEllipse(rp,cx,cy,radius,radius).

    SEE ALSO
	 AreaMove()  AreaDraw() AreaCircle()  InitArea()  AreaEnd()
	 sc:include/graphics/rastport.h  sc:include/graphics/gfxmacros.h