Nix support

[tryh4rd3rr]

this pr adds a flake.nix which can allow running
nix develop for cuda or
nix develop .#hip for hip when in the root of the repo.

---

only tested on hip as i have an amdgpu but cuda should work

[tryh4rd3rr]

will keep it a draft until i get microtex building in nix

[tryh4rd3rr]

confirmed that microtex builds and adds a symlink that gets removed when exiting the shell (it was painful)

[tryh4rd3rr]

hm, how should i add instructions in the README?

[2swap]

This is cool. I'm not a nix person, so I sort of don't feel qualified to review this at the moment... Not actually opposed to merging something like this though.
Also, is it common to just drop system-specific configuration in the base folder of the repo? This seems like a weird pattern. I would maybe pair it with the docker stuff? Or just put it in a custom nix folder? Not sure yet though.

I think your readme documentation is fine as-is :)

[tryh4rd3rr]

well, you could put the nix files in a directory, but most nix users would rather type nix develop instead of nix develop nix#default. one thing that could make the flake cleaner is instead of hardcoding /usr/include/cairo and /usr/include/gdk-pixbuf-2.0, you could use pkg-config, but that's out of the scope of this PR. lmk if you want the nix files in a dir or not, and i can change it

[meghanto]

Does this works on no-root systems where we run nix through nix-chroot? asking for a cluster :D

[tryh4rd3rr]

Does this works on no-root systems where we run nix through nix-chroot? asking for a cluster :D

not tested, idk