Add stubs for copy_to_clipboard.

src/clipboard.rs

@@ -5,7 +5,6 @@ use crate::win as platform;
 #[cfg(target_os = "linux")]
 use crate::x11 as platform;
 
-#[cfg(target_os = "macos")]
 pub fn copy_to_clipboard(data: String) {
     platform::copy_to_clipboard(data)
 }

src/win/window.rs

@@ -763,3 +763,7 @@ unsafe impl HasRawWindowHandle for Window<'_> {
         RawWindowHandle::Win32(handle)
     }
 }
+
+pub fn copy_to_clipboard(data: String) {
+    todo!()
+}

src/x11/window.rs

@@ -704,3 +704,7 @@ fn mouse_id(id: u8) -> MouseButton {
         id => MouseButton::Other(id),
     }
 }
+
+pub fn copy_to_clipboard(data: String) {
+    todo!()
+}