Import Debian changes 2:1.20.4-1

xorg-server (2:1.20.4-1) unstable; urgency=medium

  [ Timo Aaltonen ]
  * New upstream release.
    - present/wnmd: Fix use after free on CRTC removal
      (Closes: #920665).
    - xwayland: Replace xwl_window::present_window with
      ::present_flipped (Closes: #921734).

  [ Andreas Boll ]
  * Refresh 07_use-modesetting-driver-by-default-on-GeForce.diff.