xc/programs/Xserver/hw/xnest/Window.c
//bugs.freedesktop.org/show_bug.cgi?id=2546) attachment #2005
(https://bugs.freedesktop.org/attachment.cgi?id=2005): Fix Xnest to
update the shape regions in the backend server whenever a client
changes them in Xnest (the fix is to add a new wrapper which calls
|xnestShapeWindow()| before calling |miSetShape()|). Patch by Mark
McLoughlin <mark@skynet.ie>