xwayland: using %m in `wlr_log` is broken, use `wlr_log_errno` instead
xwayland: using %m in `wlr_log` is broken, use `wlr_log_errno` instead

This one was awful to track down, but calls to `wlr_log` with %m have
the errno masked by the `isatty` call in `log_stderr`. Switch them to
`wlr_log_errno` instead.

Cue quality "how can read(2) POSSIBLY be returning ENOTTY?" moments.

swaywm/wlroots,swaywm/wlroots,SirCmpwn/wlroots