Ei protocol support

- Use the configured keyboard layout, track ei seats to reconfigure their keyboards
- DBus interface
- Disambiguate input devices per backend instance
- Add support for `ei_keysym` and `ei_text`
- Act as input method for ei_text UTF-8 injection
- Create a region per output for abosolute pointer position
- Map ei region for touchscreen emulation
- Release pointer buttons and keys on removal
- Send modifiers to EI connections

src/lib.rs

@@ -177,11 +177,13 @@ pub fn run(hooks: crate::hooks::Hooks) -> Result<(), Box<dyn Error>> {
         with_xwayland,
         kiosk_command,
     );
+    // Set up the libei sender side before the backend spawns Xwayland.
+    let ei_sender = libei::setup_ei(&event_loop.handle());
+    state.common.dbus_state.set_ei_sender(ei_sender);
+
     // init backend
     backend::init_backend_auto(&display, &mut event_loop, &mut state)?;
 
-    libei::listen_eis(&event_loop.handle());
-
     if let Err(err) = theme::watch_theme(event_loop.handle()) {
         warn!(?err, "Failed to watch theme");
     }