system: prevent duplicate Wayland op

Wayland is implemented as an Op to enforce dependency and cleanup, its implementation does not allow multiple instances on a single sys object, nor would doing that make any sense.

Signed-off-by: Ophestra Umiker <cat@ophivana.moe>

internal/system/wayland.go

@@ -32,6 +32,11 @@ func (w Wayland) Type() Enablement {
 }
 
 func (w Wayland) apply(sys *I) error {
+	// the Wayland op is not repeatable
+	if sys.sp != nil {
+		return errors.New("attempted to attach multiple wayland sockets")
+	}
+
 	if err := w.conn.Attach(w.pair[1]); err != nil {
 		return fmsg.WrapErrorSuffix(err,
 			fmt.Sprintf("cannot attach to wayland on %q:", w.pair[1]))