We want the $doc, $man outputs to be symlinks pointing to nix-manual and
nix-manual.man. Creating the directories first makes the `ln` command
produce symlink $doc/${nix-manual} instead.
```
$file /nix/store/q4dwlnd36gpfajgfcp6hca2xwy068wjq-nix-2.27.1-man/rwh8ky3k040wyrywl8k2v5b3csdfbdg7-nix-manual-2.27.1-man
/nix/store/q4dwlnd36gpfajgfcp6hca2xwy068wjq-nix-2.27.1-man/rwh8ky3k040wyrywl8k2v5b3csdfbdg7-nix-manual-2.27.1-man:
symbolic link to /nix/store/rwh8ky3k040wyrywl8k2v5b3csdfbdg7-nix-manual-2.27.1-man
```
This is the reason `nix-env --help` is once again broken on 2.26/2.27/master
after 4108529.
This should fix a few packaging regressions.
`dev` also includes a merged `includes/`, which may be helpful until
inter-component includes are fixed properly.
1. Fix this eval error:
https://hydra.nixos.org/jobset/nix/master#tabs-errors
The dev package output (actually a separate derivation) needs to skip
this for cross just as the main package output does.
2. Deduplicate libs attrset and list.
3. Move `nix-functional-tests` to `checkInputs`.
With the Meson build system, we no longer need a `check` vs
`install-check` distinction, so it is simpler to just keeep
everything in one place.
The new package output attributes are somewhat experimental, and
provided for compatibility most of all.
We'll see how well this goes before the changes proposed in
https://github.com/NixOS/nix/issues/6507
This ensures just `nix build`-ing the flake doesn't forget to run all
tests. One can still specifiy specific attributes to just build one
thing.
Co-authored-by: Robert Hensing <roberth@users.noreply.github.com>
