(C) 1998 AROS - The Amiga Research OS
SPOS_RELATIVE (or NULL) moves the screen by a delta of x1,y1.
SPOS_ABSOLUTE moves the screen to the specified position x1,y1.
SPOS_MAKEVISIBLE moves an oversized scrolling screen to make the rectangle (x1,y1),(x2,y2) visible x1,y1 - Absolute (SPOS_ABSOLUTE) or relative (SPOS_RELATIVE) coordinate