Black/frozen screen on sway with Apple Silicon

[fx-chun]

This is more of a general heads-up for overlay users who are on Apple Silicon than an issue with the overlay (so no one goes down the same rabbit hole as me).

wlroots currently doesn't do detection of explicit sync support when initializing the DRM backend:
https://gitlab.freedesktop.org/wlroots/wlroots/-/issues/3904

This will cause sway to freeze the TTY or show a black screen, depending on what backends you have enabled. You will see an error relating to drmSyncobjCreate when inspecting logs from sway -d.

The solution is to set WLR_RENDER_NO_EXPLICIT_SYNC=1.