xwayland: Include xwayland-window.h from xwayland-glamor-eglstream.c

Fixes build failure.

Closes: xorg/xserver#954
Fixes: 89e32d00 "xwayland: Move Xwayland windows to its own sources"
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Olivier Fourdan <ofourdan@redhat.com>
3 jobs for xwayland-eglstream-xwl_window in 13 minutes and 8 seconds (queued for 1 second)
Status Job ID Name Coverage
  Docker Image
passed #1281481
debian-testing

00:06:20

 
  Build And Test
passed #1281482
autotools-build-and-test

00:06:48

passed #1281483
meson-build-and-test

00:02:20