Pass Command Line arguments to Apache Ant build file from DITAOT custom plugin

Configuring parameter default value in plugin.xml doesn't actually set the property default value. DITA-OT only uses the information when generating documentation for plug-ins.

You have to handle the default value in the build.xml. DITA-OT built-in plug-ins use the following convention:

<project>
  <!--
  This is the enty point DITA-OT will call when running html5-test.
  In depends first call your own init target, then normal HTML5 target.
  -->
  <target name="dita2html5-test"
          depends="html5-test.init,
                   dita2html5"/>
  <target name="html5-test.init">
    <!--
    Since property values cannot be overwritten once set, this will only
    set the value if there is no value set from the command line.
    -->
    <property name="args.artlbl" value="no"/>
  </target>

</project>