SDL: Make non-Mac fullscreen cursor visible

Issue: cebix/macemu#26

On non-Mac platforms, driver_fullscreen constructor sets up software cursor,
but switch_to_current_mode() ask for a hardware cursor, possibly due to a typo.
Neither one ends up being drawn, so the cursor goes invisible.

This change makes them agree to use a software cursor. We should eventually
move to just one place deciding which cursor to use, so they don't have to be
kept in sync.

BasiliskII/src/SDL/video_sdl.cpp

@@ -1537,13 +1537,13 @@ void SDL_monitor_desc::switch_to_current_mode(void)
 #ifdef SHEEPSHAVER
 bool video_can_change_cursor(void)
 {
+	if (display_type != DISPLAY_WINDOW)
+		return false;
+
 #if defined(__APPLE__)
 	static char driver[] = "Quartz?";
 	static int quartzok = -1;
 
-	if (display_type != DISPLAY_WINDOW)
-		return false;
-
 	if (quartzok < 0) {
 		if (SDL_VideoDriverName(driver, sizeof driver) == NULL || strncmp(driver, "Quartz", sizeof driver))
 			quartzok = true;