Both nix and rustix used in the dependency chain

[ChrisDryden]

I was looking into the different dependency chains more specifically in the stty package but also in the shared libraries and it was interesting to me how we have rustix in the dependency tree for every utility through the clap dependency. Given that both of these libraries should have the same functionality was wondering if it would be useful to move some of the nix usage over to rustix for the windows support.

I've also attached an example full build profile for stty that has the two PR's applied to show the speed improvements and the critical build paths:

[sylvestre]

Yeah, we might want to use only one. Thanks

[oech3]

~I can't find list of BaudRates at rustix's src.~ Maybe, auto closes #8719 too?

[ChrisDryden]

I've been experimenting with it and I think it actually would solve the issue, I had a script to replicate the error in docker just confirming that it works now