Thanks to two different pilot errors on my part, I have broken the packaging system of two OSes that package marcel. I would have had no idea they were including marcel otherwise. In any case, I'm happy to know that Arch Linux, and nixpkgs (so headed to NixOS, I believe), now include marcel.
While we're on the topic: I need help with marcel, especially in porting.
I occasionally observe marcel running on MacOS. But this usually requires the security-related fiddling characteristic of recent MacOS versions. I don't really know what I'm doing, or how to get things running more smoothly. And I haven't run the full test suites there.
I know for a fact that marcel doesn't work on Windows, because people have tried. I believe the first roadblock is the lack of readline support. And beyond that (way beyond that), I don't have even the first clue about packaging for Windows.
If you like marcel, and want to help getting it run on MacOS or Windows, please get in touch, I'd love to work with someone on this.