fix: handle X11 connection loss gracefully

[jubalh]

Use XSetIOErrorExitHandler on X11 to detect connection loss and disable GTK features (tray, clipboard, notifications).

[aw32]

I tested this.
The _x_io_error_handler (which is an io error exit handler) is not called.
Apparently you also need to register an io error handler with XSetIOErrorHandler.
I tried that and then both handlers are called and profanity continues to run.
Thanks for your ongoing work in the niche xmpp ecosystem. ❤️

[jubalh]

I tried that and then both handlers are called and profanity continues to run.

Do you have a patch? :)

[paulfertser]

I tried that and then both handlers are called and profanity continues to run.

Do you have a patch? :)

Github doesn't let attach a patch, lol. OK, renamed to .txt.

0001-fix-handle-X11-connection-loss-gracefully.txt

[jubalh]

Thank you for the patch @paulfertser !
I'll additionally add you to Co-authored-by and push the new changes here.

[jubalh]

I'll wait for your review before merging.

[paulfertser]

Passes my testing and LGTM, thank you! :)
A sidenote, if you ever decide to try to re-init Gtk (like to have that tray working after X restart, not sure what would be a meaningful trigger to attempt it though) you'll need to reinstall the handlers after that, also it would be racy (if the server exits again before you had a chance to reinstall handlerls then the whole app crashes).