Contributing back changes we're using at rv

[deivid-rodriguez]

Hello @nmoutschen and @aminya 👋 👋

We've been using this library in https://github.com/spinel-coop/rv for a while now, and it's working reasonably fine so far.

We've also included all the fixes in @aminya's fork, because we found them useful too ❤️.

It'd be great to join forces and give this repo some love again, so I'm proposing this PR to sync back the changes we're currently using. Although I understand you may no longer be interested since it has been a while since this repo got activity 🙏.

Anyways, thanks both for the great work!

[aminya]

Thanks for the PR. It would be easier to review this if @nmoutschen merged my PR first.
I haven't seen any activity, though.

[deivid-rodriguez]

Hei @aminya! Absolutely, it'd be better to merge your PR first, and then discuss our changes on top of that. If your PR moves forward, I'm more than happy to rebase this :)

The story behind this PR is essentially:

• We needed some changes over current dep-graph implementation in rv, so initially we started vendoring a custom dep-graph inside rv, but it was in our plans to try contribute back our work if dep-graph turned out to work well for our use case.
• It's indeed been working great, but dep-graph tests have been getting in the middle of our build, because sometimes they hang or take a long time, so we offboarded our vendored copy to our own fork.
• After doing that, it seemed like a good time to start a discussion upstream to try give this library some love, and a PR with all the changes that we are using seemed like a good way to do that :)

At this point I think we'd ideally figure out how to contact @nmoutschen and see if he's interested in maintaining this repo and if not, get some more maintainers added or figure out a transition to a new home.