Fix UIKit CI (#122)

Author: bbrk24

Sources/UIKitBackend/UIKitBackend+Menu.swift

@@ -10,6 +10,7 @@ extension UIKitBackend {
         return Menu()
     }
 
+    @available(tvOS 14, *)
     static func buildMenu(
         content: ResolvedMenu,
         label: String,
@@ -34,7 +35,11 @@ extension UIKitBackend {
     public func updatePopoverMenu(
         _ menu: Menu, content: ResolvedMenu, environment _: EnvironmentValues
     ) {
-        menu.uiMenu = UIKitBackend.buildMenu(content: content, label: "")
+        if #available(iOS 14, macCatalyst 14, tvOS 17, *) {
+            menu.uiMenu = UIKitBackend.buildMenu(content: content, label: "")
+        } else {
+            preconditionFailure("Current OS is too old to support menu buttons.")
+        }
     }
 
     public func updateButton(

Sources/UIKitBackend/UIKitBackend.swift

@@ -246,7 +246,9 @@ open class ApplicationDelegate: UIResponder, UIApplicationDelegate {
     /// point in your implementation. If you do not, then calls to
     /// ``SwiftCrossUI/Scene/commands(_:)`` will have no effect.
     open override func buildMenu(with builder: any UIMenuBuilder) {
-        guard builder.system == .main else { return }
+        guard #available(tvOS 14, *),
+            builder.system == .main
+        else { return }
 
         for submenu in menu {
             let menuIdentifier = mapMenuIdentifier(submenu.label)

Sources/UIKitBackend/Widget.swift

@@ -273,7 +273,7 @@ class BaseControllerWidget: UIViewController, WidgetProtocolHelpers {
                 at: parentWidget.childWidgets.firstIndex { $0 === self }!)
             self.parentWidget = nil
         }
-        if let parent {
+        if parent != nil {
             willMove(toParent: nil)
             removeFromParent()
         }