Previously, not passing `--base` would enforce the most strict checks.
While there's currently no actual violation of these stricter checks,
this does not match the previous behavior.
This won't matter once CI passes `--base`, the code handling the
optionality can be removed then.
This implements the option for a gradual migration to stricter checks.
For now this is only done for the check against empty non-auto-called
callPackage arguments, but in the future this can be used to ensure all
new packages make use of `pkgs/by-name`.
This is implemented by adding a `--base <BASE_NIXPKGS>` flag, which then
compares the base nixpkgs against the main nixpkgs version, making sure
that there are no regressions.
The `--version` flag is removed. While it was implemented, it was never
used in CI, so this is fine.
This introduces the `pkgs/by-name` directory as proposed by RFC 140.
Included are:
- The implementation to add packages defined in that directory to the
top-level package scope
- Contributer documentation on how to add packages to it
- A GitHub Actions workflow to check the structure of it on all PRs
