Register a dpy_gfx_setdata callback so that the Cocoa code
is notified whenever the screen start address changes.
Commit 1d3323d has a similar fix for the VNC UI.
Signed-off-by: Henry Harrington <henry.harrington@gmail.com>
Cc: qemu-stable@nongnu.org (1.3.x)
Signed-off-by: Andreas Färber <andreas.faerber@web.de>