We're sorry to report that there are some problems with our git repositories at the moment, resulting in 'early EOF / index-pack failed' messages when users are attempting to clone one of our repositories.
The problem has been thoroughly analyzed, but even after many hours of analysis, no solution has been found yet. Your best chance is to keep re-trying the clone, in 5-10% of the cases it will succeed.
More technical details are available at this posting to the git mailing list:
Sorry for the inconvenience.