Fix javac target in build.xml

build.xml

@@ -34,7 +34,7 @@
     </target>
     <target name="compile" depends="init">
         <echo message="creating ${plugin.jar}"/>
-        <javac srcdir="src" classpath="${josm}" debug="true" destdir="${plugin.build.dir}">
+        <javac srcdir="src" classpath="${josm}" debug="true" target="${ant.build.javac.target}" destdir="${plugin.build.dir}">
             <compilerarg value="-Xlint:deprecation"/>
             <compilerarg value="-Xlint:unchecked"/>
         </javac>