On macOS, open builds of jdk10/master (now jdk/jdk) have started to print "xattr: No such file" message recently. I initially thought this was jlink but it's something else. Others have noticed this too.

WARNING: Using incubator modules: jdk.incubator.httpclient
WARNING: Using incubator modules: jdk.incubator.httpclient
xattr: No such file: /d/jdk/open/build/macosx-x86_64-normal-server-release/images/jre-bundle/jre-10.jre/Contents/Home/legal/java.activation/LICENSE
xattr: No such file: /d/jdk/open/build/macosx-x86_64-normal-server-release/images/jdk-bundle/jdk-10.jdk/Contents/Home/legal/java.activation/LICENSE
Stopping sjavac server
Finished building target 'images' in configuration 'macosx-x86_64-normal-server-release'