Missing jar reference in helloworld plugin's build.xml

I downloaded flume 0.9.3 and was playing around with the helloworld plugins. The default "build.xml" seems to be missing a line that can include the slf4j related jars and this especially affects HelloWorldSource.java as it seems to depend on the same. FYI, I included the following line "<include name="*/slf4j-.jar" />" to have ant successfully compile the plugin.