x11-wm/gamescope: update to 3.11.51

Changes: https://github.com/Plagman/gamescope/compare/3.11.49...3.11.51
Reported by: Repology, portscout

(cherry picked from commit bc1d9770a8d994898456c311c87049713ce61bc1)
(cherry picked from commit a4966e5cca1911cd976444829addf2cb7692f4de)
(cherry picked from commit 05356a1b1a22881da4439ce036cf86fc860dc740)
(cherry picked from commit 54c4ff9ec5739b78342421fc7f329371b8b6a037)