It passed for me. Where did you get the diehard test? If you compiled it directly from http://www.stat.fsu.edu/pub/diehard/ then it is because that source is broken.
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.
