dev-libs/wayland: Fix some undefined behaviour

Upstream merge request:
https://gitlab.freedesktop.org/wayland/wayland/-/merge_requests/152

BUG=chromium:1227753
TEST=Ran wayland test suite under ubsan

Change-Id: I0d5587c7a50f63e0940304ef15071b5fb4fe1018
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/overlays/portage-stable/+/3016224
Tested-by: Fergus Dall <sidereal@google.com>
Auto-Submit: Fergus Dall <sidereal@google.com>
Reviewed-by: David Munro <davidmunro@google.com>
Commit-Queue: Fergus Dall <sidereal@google.com>
3 files changed