tmux: install manpages

[iblech]

Motivation for this change

On current master, man tmux comes empty after in a nix-shell -p tmux. This pull request fixes that.

However, I'm a little bit unsure whether this is the correct procedure. I looked at other packages for guidance, but didn't spot a consistent pattern. The packages feh and vdr both use multiple outputs, as tmux did before this pull request; the manpages for feh are installed correctly and these for vdr are not.

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS linux)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Ensured that relevant documentation is up to date
• Fits CONTRIBUTING.md.

[prusnak]

I think this line is redundant if you only want to have the "out" output.

[teto]

I dom't believe removing the man output is the solution.
I am not sure how nix-shell and MANPATH interact
nix-shell --pure -p tmux.man man does not find the man but my installed tmux brings up the manpage

[iblech]

I think this line is redundant if you only want to have the "out" output.

Oh yes, I agree. I'll change this in a second.

[iblech]

I dom't believe removing the man output is the solution.
I am not sure how nix-shell and MANPATH interact
nix-shell --pure -p tmux.man man does not find the man but my installed tmux brings up the manpage

Okay, weird, it doesn't work for me. But it's not terribly important. I'll await further guidance how to proceed. :-) Thank you two of your review!

[Ma27]

👎 the multiple-output feature exists for a reason: https://nixos.org/nixpkgs/manual/#chap-multiple-output

I'm not 100% sure why the MANPATH isn't properly configured on nix-shell, you may want to file an issue here instead since a lot more packages are utilizing this pattern.

The packages feh and vdr both use multiple outputs, as tmux did before this pull request; the manpages for feh are installed correctly and these for vdr are not.

Is it possible that feh is installed in your local profile or your system and that's why the man-pages are found?

[doronbehar]

This should be closed in favor of either of:

• Certain paths don't link if multi outputs are used #65325
• document nix-env bug relating to multiple output installation #76794

[iblech]

Thank you @doronbehar, I agree this should be closed in favor of the other issues/pull requests. I did not notice these before. Thank you for your work on our documentation system!