Missing call to flush_display_lineregion() for SDL in PILOTBITBLT

When the target for a PILOTBITBLT operation is the display bitmap,
and the display bitmap is not memory-mapped from the actual display,
the display subsystem needs to be notified to flush the Lisp display
bitmap to the display so that changes are immediately visible.
The mechanism was present for X11 displays but needed to be implemented
for SDL displays.

Author: nbriggs

src/bitblt.c

@@ -126,7 +126,7 @@ LispPTR N_OP_pilotbitblt(LispPTR pilot_bt_tbl, LispPTR tos)
   if (displayflg) (currentdsp->mouse_visible)(IOPage->dlmousex, IOPage->dlmousey);
 #endif /* SUNDISPLAY / DOS */
 
-#ifdef XWINDOW
+#if defined(XWINDOW) || defined(SDL)
   flush_display_lineregion(dx, dstbase, w, h);
 #endif /* XWINDOW */