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.
Use new dune based build system. This no longer has a way to
enable the non-minimal build. As it turns out, though, no
package required that (and it was impossible to get a non-minimal
extlib build from OPAM before anyways).
The old expression needs to be retained for extlib 1.7.7 and just
moved over.
Unfortunately there's no way to get Haxe 4.0 and 4.1 to work with extlib
1.7.8 (not even without the minimal install), so we need to package
1.7.7 again, at least until 1.7.9 (?) brings backwards compatibility
packages, hopefully.
