The build.gradle file currently contains the logic to build maven artifacts. This should be moved to its own file, see https://bugs.openjdk.org/browse/JDK-8333146 .

In the meantime, the code that is in build.gradle needs to be adjusted to work with recent gradle versions. Instead of
`classifier "$t.name"` we should now use `archiveClassifier.set(t.name)`

Without this fix, publishing to Maven local (using `sh gradlew -PMAVEN_PUBLISH=true publishToMavenLocal`) fails.