package/x11r7/xserver_xorg-server: fix CLOCK_MONOTONIC detection for Xwayland

package/x11r7/xserver_xorg-server: fix CLOCK_MONOTONIC detection for Xwayland

Commit d119a6b1c0cb90089a6451f5a3c112944e406a4f
("package/x11r7/xserver_xorg-server: add missing dependency for
wayland support") is not sufficient to fix a build with wayland
support based the configuration at:

  http://autobuild.buildroot.net/results/cf0/cf026e9b18e86b9890341612050f4d166a7b822d/

The build errors out at a later stage during configure:

  configure: error: Xwayland requires CLOCK_MONOTONIC support.

This commit adds a patch from OpenEmbedded to fix the problem.

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>