Dune (in Coq lang mode) requires COQPATH, contrary to other tools such
as coq_makefile.
I used an AI for the last step: getting the suggestion of using
`preBuild` instead of `env`.
Assisted-by: Copilot:Claude Haiku 4.5
Make the defauult prefix be set to `[ "rocq" ]` (instead of
`[ "rocq-core" ]`) if `useCoq` is `false`.
This matches the opam convention and ensures that the default
`opam-name` will be correct.
Make the default prefix be set to `[ "coq" ]` if `useCoq` is `true`.
This ensures that `mkRocqDerivation` can be called directly to build
Coq derivations without changing the derivation name / `opam-name`.
Format all Nix files using the officially approved formatter,
making the CI check introduced in the previous commit succeed:
nix-build ci -A fmt.check
This is the next step of the of the [implementation](https://github.com/NixOS/nixfmt/issues/153)
of the accepted [RFC 166](https://github.com/NixOS/rfcs/pull/166).
This commit will lead to merge conflicts for a number of PRs,
up to an estimated ~1100 (~33%) among the PRs with activity in the past 2
months, but that should be lower than what it would be without the previous
[partial treewide format](https://github.com/NixOS/nixpkgs/pull/322537).
Merge conflicts caused by this commit can now automatically be resolved while rebasing using the
[auto-rebase script](8616af08d9/maintainers/scripts/auto-rebase).
If you run into any problems regarding any of this, please reach out to the
[formatting team](https://nixos.org/community/teams/formatting/) by
pinging @NixOS/nix-formatting.
