Gluegen compilation with ANT

I have just spent two days googling and trying various things to compile Gluegen. Every time I ended with message

BUILD FAILED
/scratch/hanousek/gluegen2-2.0-rc5/make/build.xml:627: The following error occurred while executing this line:
/scratch/hanousek/gluegen2-2.0-rc5/make/build.xml:156: Problem: failed to create task or type antlr
Cause: the class org.apache.tools.ant.taskdefs.optional.ANTLR was not found.
        This looks like one of Ant's optional components.
Action: Check that the appropriate optional JAR exists in
        -/software/ant-1.9/1.9.4/lib
        -/root/.ant/lib
        -a directory added on the command line with the -lib argument
Do not panic, this is a common problem.
The commonest cause is a missing JAR.
This is not a bug; it is a configuration problem

Of course I had tried to install ANTLR, ATNLRv3 and even ANTLRv4, but with no success. Things like

ant -Dantlr.jar=/software/ant-1.9/1.9.4/lib/antlr.jar -Djunit.jar=/software/ant-1.9/1.9.4/lib/junit-4.11.jar

didn't work so don't spend a lot of time with that.
The solution is finally quite simple. Developers says that it should work with ant >= 1.8. This is wrong, at least for version 1.9.4 which I had installed. When I tried to use ant-1.6 and edited file make/build.xml to remove the ant version requirement section, everything went OK.