(Fpos_visible_in_window_p): New arg to compute_motion.

src/window.c

@@ -242,7 +242,7 @@ POS defaults to point; WINDOW, to the selected window.")
 	return Qnil;
 
       /* If that info is not correct, calculate afresh */
-      posval = *compute_motion (top, 0, (hscroll ? 1 - hscroll : 0),
+      posval = *compute_motion (top, 0, (hscroll ? 1 - hscroll : 0), 0,
 				posint, height, 0,
 				window_internal_width (w) - 1,
 				hscroll, 0, w);