--- build.xml.orig	2010-11-27 07:42:11.000000000 +1100
+++ build.xml	2011-12-01 05:56:14.000000000 +1100
@@ -430,6 +430,7 @@
       <arg value="targetDirectory=${build.docs}"/>
       <arg value="${build.dir}/xdocs/docs-book.xml"/>
       <arg value="${build.dir}/xdocs/style"/>
+      <jvmarg value="-Djava.awt.headless=true"/>
     </java>
 
     <copy file="${docs.dir}/download.cgi" tofile="${build.docs}/download.cgi"/>
