Solution 06 is quite good (maybe perfect) from the perspective of binary compatibility. For a while I thought I am going to give up, however then I noticed that there is an added overloaded method. With proper parameters this can cause the previously OK source to become uncompilable.

<?xml version="1.0" encoding="UTF-8"?>

<!-- this is a template file to test  -->

<project name="testing-template" default="run" basedir=".">

    <import file="../../common.xml"/>

</project>