Try using Dieharder. It incorporates most of the Diehard tests, as well as other tests and is much more rigorous.

sudo apt-get install dieharder

http://www.phy.duke.edu/~rgb/General/dieharder.php

If you make a GSL interface for the RNG it will make using dieharder much easier

I actually tried a modified OCaml implementation of a very simple test. The issue is probably due to bad seeding/initialization: if I use the given static seed, it passes, but if I try to provide any other seed, it fails on at least one test.

I'll try to find a more complete/better tested port, or try to do it myself.