It is different from dev-java/ant-antlr, and it is required to build some build.xmls with tags like: <antlr:ant-antlr3> Reproducible: Always
ant-* ant task are special or in other words reserved for ants own tasks. I suggest antlr-ant:3 as the package, though I wonder if we shouldn't just build the task with antlr:3 instead, after all it's the same source tarball.
Created attachment 318358 [details] ant-antlr3-20101230.ebuild I'm not sure, that an additional slot should be used instead of additional package (they use different version naming scheme). I think it can be easily fixed. Comments are welcome! :)
The download for this has disappeared (I did look quite hard) and I don't think anybody ever used it anyway. Few projects even use the Apache antlr v2 task. Closing.