Fix stdlib compiling

Author: noti0na1

library/src/scala/annotation/nullTrackable.scala

@@ -1,3 +1,10 @@
 package scala.annotation
 
-final class nullTrackable extends StaticAnnotation
+/** An annotation that can be used to mark a mutable field as trackable for nullability.
+ *  With explicit nulls, a normal mutable field can be tracked for nullability by flow typing,
+ *  since it can be updated to a null value at the same time.
+ *  This annotation will force the compiler to track the field for nullability, as long as the
+ *  prefix is a stable path.
+ *  See `tests/explicit-nulls/pos/force-track-var-fields.scala` for an example.
+ */
+final class nullTrackable extends StaticAnnotation

project/Build.scala

@@ -1141,6 +1141,7 @@ object Build {
         file(s"${baseDirectory.value}/src/scala/annotation/init.scala"),
         file(s"${baseDirectory.value}/src/scala/annotation/unroll.scala"),
         file(s"${baseDirectory.value}/src/scala/annotation/targetName.scala"),
+        file(s"${baseDirectory.value}/src/scala/annotation/nullTrackable.scala"),
         file(s"${baseDirectory.value}/src/scala/deriving/Mirror.scala"),
         file(s"${baseDirectory.value}/src/scala/compiletime/package.scala"),
         file(s"${baseDirectory.value}/src/scala/quoted/Type.scala"),
@@ -1278,6 +1279,7 @@ object Build {
         file(s"${baseDirectory.value}/src/scala/annotation/init.scala"),
         file(s"${baseDirectory.value}/src/scala/annotation/unroll.scala"),
         file(s"${baseDirectory.value}/src/scala/annotation/targetName.scala"),
+        file(s"${baseDirectory.value}/src/scala/annotation/nullTrackable.scala"),
         file(s"${baseDirectory.value}/src/scala/deriving/Mirror.scala"),
         file(s"${baseDirectory.value}/src/scala/compiletime/package.scala"),
         file(s"${baseDirectory.value}/src/scala/quoted/Type.scala"),