Ant 1.8 gives the following warning
[javac] build.xml:9: warning: 'includeantruntime' was not set,
defaulting to build.sysclasspath=last; set to false for repeatable builds
Beacuse a feature introduced in the 1.8 version.. easyly solved by adding
<presetdef name="javac">
<javac includeantruntime="false" />
</presetdef>
in the beginning in build.xml