I was interested to see that Flynn is using tup[0] for their build system. I always thought it seemed interesting, but hadn't really noticed any high-profile projects using it.
Yeah, tup is neat. Much lower friction than the equivalent Makefiles as it can auto-detect dependencies and outputs in many cases. We've run into a couple issues, but for the most part it's been smooth sailing.
I'd be interested to hear some of the common issues you've had with tup and the solutions if you're ever looking for a blog post topic :)