Merge changes from apertis/v2020-security into apertis/v2020

Signed-off-by: Andrew Lee (李健秋) <andrew.lee@collabora.co.uk>

xorg-server (2:1.20.4-1+deb10u1) buster-security; urgency=high

  * Non-maintainer upload by the Security Team.
  * Fix for ZDI-11426 (CVE-2020-14347) (Closes: #968986)
  * Correct bounds checking in XkbSetNames() (CVE-2020-14345)
  * Fix XIChangeHierarchy() integer underflow (CVE-2020-14346)
  * Fix XkbSelectEvents() integer underflow (CVE-2020-14361)
  * Fix XRecordRegisterClients() Integer underflow (CVE-2020-14362)