fix: feature gate

examples/application/src/main.rs

@@ -282,6 +282,7 @@ impl cosmic::Application for App {
                         .progress(1.0)
                         .width(Length::Fill),
                 )
+                .push(widget::button::suggested("asdf").on_press(Message::Ignore))
                 .spacing(cosmic::theme::spacing().space_s)
                 .width(Length::Fill)
                 .height(Length::Shrink)

src/surface/mod.rs

@@ -80,6 +80,7 @@ pub enum Action {
     Task(Arc<dyn Fn() -> Task<Action> + Send + Sync>),
 }
 
+#[cfg(feature = "winit")]
 pub fn surface_task<M: Send + Sync + 'static>(action: Action) -> Task<crate::Action<M>> {
     crate::task::message(crate::Action::Cosmic(crate::app::Action::Surface(action)))
 }