Generate real enums instead of enum-like classes (#1198)

Co-authored-by: Levi Lesches <[email protected]>

Author: Levi-Lesches

pkgs/ffigen/CHANGELOG.md

@@ -3,6 +3,10 @@
 - __Breaking change__: Code-gen the ObjC `id` type to `ObjCObjectBase` rather
   than `NSObject`, since not all ObjC classes inherit from `NSObject`. Eg
   `NSProxy`.
+- __Breaking change__: Enums are now generated as real Dart enums, instead of
+  abstract classes. Since Dart enums cannot be empty, empty native enums are
+  generated as empty sealed classes. Native enum members with duplicate integer
+  values are handled properly, and are equal to each other in Dart as well.
 - Rename ObjC interface methods that clash with type names. Fixes
   https://github.com/dart-lang/native/issues/1007.
 

pkgs/ffigen/analysis_options.yaml

@@ -15,6 +15,7 @@ analyzer:
     - example/objective_c/**
     - example/swift/**
     - test_flutter/native_objc_test/**
+    - test/native_objc_test/**
   language:
     strict-casts: true
     strict-inference: true