And in an interesting twist, it seems that BitKeeper is now Open Source anyway (or at least I see "Now available as Open Source under the Apache 2.0 License" on their webpage) meaning that this could all have been avoided
Larry McVoy comments here occasionally as https://news.ycombinator.com/user?id=luckydude
People have noted multiple times that its current build system is fairly hostile to packaging on *NIX, but nobody seems to be putting in the work and the time. I'm somewhat curious about BitKeeper, but not enough to make my first goal to go down into its guts (complete with a custom stdio from NetBSD with modifications!) to make it play nicely with my system.
[1] https://users.bitkeeper.org/t/thoughts-after-a-few-days-with...