I think Arne, if he is around, can tell you more about ant in OS X. But AFAIK the ant binary distribution, which you should be able to use without problems, contains a shell script to execute ant easily.
For Phex it should be fine to use ant 1.6.5, not sure if its easier, but I also still use it.
Phex compilation doesn't take very long. If you have a output\lib\phex.jar file you can expect that the build finished correctly.

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