INT 62 u - FGDRIVER v4.02 - "FG_DRAWRELX" - XOR SOLID LINE TO RELATIVE POSITION
	AX = 0021h
	BX = endpoint column offset
	CX = endpoint row offset
Desc:	draw a solid line, XORing each pixel onto the screen
Notes:	the FGDRIVER functions are rearranged with each major release, but
	  their parameters do not change (see #03474 at AX=0000h)
	This call is ignored in text modes
	The starting point is the current graphics cursor position; the cursor
	  position is updated
SeeAlso: AX=0006h,AX=000Dh,AX=001Dh,AX=0020h,AX=0026h,AX=0090h