Add canImport check for UIKit

Author: rwbutler

FeatureFlags/Classes/UI/Feature Flags/Shared/UIControl.swift

@@ -7,6 +7,8 @@
 
 import Foundation
 import ObjectiveC
+#if canImport(UIKit)
+import UIKit
 
 public extension NSObject {
     func associatedObject<T>(key: UnsafeRawPointer, makeDefault: () -> T) -> T {
@@ -43,3 +45,4 @@ public extension UIControl {
         }
     }
 }
+#endif

Package.swift

@@ -10,7 +10,8 @@ let package = Package(
     products: [
         .library(
             name: "FeatureFlags",
-            targets: ["FeatureFlags"])
+            targets: ["FeatureFlags"]
+        )
     ],
     targets: [
         .target(