ninja as-is works reasonably well for many projects, and it's reasonably small and simple.

But it doesn't work great for all use-cases, and there are many pull requests for adding "heavy" dependencies (e.g. make jobserver support #1139 / #1140, a persistent daemon #1389 / #1438, some configurable frontend thingy with a message-passing interface #1210).

One half-baked idea would be to make the core ninja code a "real" library, and then keep the regular ninja binary reasonably small and focused, and then add a second binary somewhere (contrib/monster or what have you) that links to the ninja library and adds all these features. That binary could then depend on all kinds of stuff.

I haven't thought this through, but I figured I should at least write it down :-)