Add -ObjC linker flag to UIKitNavigation target

[connor-krazy7]

Summary

When UIKitNavigation is built as a dynamic framework (e.g. in a modularized project with multiple dynamic targets), the linker dead-strips ObjC symbols from UIKitNavigationShim because no Swift code references them directly. This causes an "unrecognized selector" crash at runtime:

-[MyViewController set_UIKitNavigation_onDismiss:]: unrecognized selector sent to instance

The UIKitNavigationShim target contains ObjC code that:

• Swizzles viewDidAppear:/viewDidDisappear: via +load
• Adds categories on UIViewController (set_UIKitNavigation_onDismiss:, set_UIKitNavigation_hasViewAppeared:, etc.)

Adding -ObjC to UIKitNavigation's linker settings forces the linker to include all ObjC categories from the statically linked UIKitNavigationShim target, fixing the crash.

Reproduction

1. Create a project with multiple dynamic framework targets
2. Have one target depend on UIKitNavigation (e.g. via ComposableArchitecture)
3. Use present(item:content:) to present a view controller
4. Crash on set_UIKitNavigation_onDismiss: unrecognized selector

[mbrandonw]

Hi @connor-krazy7, packages are allowed to use unsafe flags only in Swift 6.2 and up (see this discussion), and so at the very least this would necessitate moving this Package.swift to Package‌@swift-6.0.swift and creating a new Package.swift for 6.2.

[connor-krazy7]

Hi @connor-krazy7, packages are allowed to use unsafe flags only in Swift 6.2 and up (see this discussion), and so at the very least this would necessitate moving this Package.swift to Package‌@swift-6.0.swift and creating a new Package.swift for 6.2.

Thanks for the comment,