Fix unused type warnings in i-slint-backend-linukxms build with default features

When no features are enabled, the TimerBasedAnimationDriver would be unused.

internal/backends/linuxkms/display.rs

@@ -1,9 +1,6 @@
 // Copyright © SixtyFPS GmbH <info@slint.dev>
 // SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-Slint-Royalty-free-2.0 OR LicenseRef-Slint-Software-3.0
 
-use std::cell::Cell;
-use std::rc::{Rc, Weak};
-
 use i_slint_core::api::PhysicalSize;
 use i_slint_core::platform::PlatformError;
 
@@ -101,13 +98,19 @@ impl RenderingRotation {
     }
 }
 
-struct TimerBasedAnimationDriver {
+#[cfg(any(feature = "renderer-skia-vulkan", feature = "renderer-software"))]
+pub(crate) mod timeranimations {
+    use i_slint_core::platform::PlatformError;
+    use std::cell::Cell;
+    use std::rc::{Rc, Weak};
+
+    pub(crate) struct TimerBasedAnimationDriver {
         timer: i_slint_core::timers::Timer,
         next_animation_frame_callback: Cell<Option<Box<dyn FnOnce()>>>,
     }
 
     impl TimerBasedAnimationDriver {
-    fn new() -> Rc<Self> {
+        pub(crate) fn new() -> Rc<Self> {
             Rc::new_cyclic(|self_weak: &Weak<Self>| {
                 let self_weak = self_weak.clone();
                 let timer = i_slint_core::timers::Timer::default();
@@ -156,3 +159,4 @@ impl crate::display::Presenter for TimerBasedAnimationDriver {
             Ok(())
         }
     }
+}

internal/backends/linuxkms/display/swdisplay/linuxfb.rs

@@ -12,7 +12,7 @@ pub struct LinuxFBDisplay {
     back_buffer: RefCell<Box<[u8]>>,
     width: u32,
     height: u32,
-    presenter: Rc<crate::display::TimerBasedAnimationDriver>,
+    presenter: Rc<crate::display::timeranimations::TimerBasedAnimationDriver>,
     first_frame: Cell<bool>,
 }
 
@@ -87,7 +87,7 @@ impl LinuxFBDisplay {
             back_buffer,
             width,
             height,
-            presenter: crate::display::TimerBasedAnimationDriver::new(),
+            presenter: crate::display::timeranimations::TimerBasedAnimationDriver::new(),
             first_frame: Cell::new(true),
         }))
     }

internal/backends/linuxkms/display/vulkandisplay.rs

@@ -173,6 +173,6 @@ pub fn create_vulkan_display() -> Result<VulkanDisplay, PlatformError> {
         queue_family_index,
         surface: vulkan_surface,
         size,
-        presenter: crate::display::TimerBasedAnimationDriver::new(),
+        presenter: crate::display::timeranimations::TimerBasedAnimationDriver::new(),
     })
 }