Fixes this warning (and clipboard support) on Wayland:

[2026-05-18T09:49:48Z WARN  egui_winit::clipboard] Failed to initialize arboard clipboard: Unknown error while interacting with the clipboard:
  X11 server connection timed out because it was unreachable

From the arboard crate description:

However, Wayland is becoming the majority default as of 2025. Some distributions are even considering the removal of X by default. To support Wayland correctly, arboard users should enable the wayland-data-control feature. If enabled, it will be prioritized over the X clipboard.

Wayland support is not enabled by default because it may be counterintuitive to some users: it relies on the data-control protocol extension(s), which are not supported by all Wayland compositors. You can check compositor support on wayland.app [...]

Related

• Wayland dependencies are pulled in for eframe, even when wayland feature is disabled. #4538
• Fix unspecified wayland/x11 dep from clipboard feature #5478

The problem is that cargo won't let us specify "if both wayland and clipboard are enabled, also enable smithay" without more shenanigans.