ncurses: Create libtinfo symlink

[spacekitteh]

Some applications expect libtinfo to be a separate library to libncurses; this fixes that.

Fedora's workaround which does the same thing: commercialhaskell/stack#1012 (comment)

Arch's: https://aur.archlinux.org/packages/ncurses5-compat-libs/

Gentoo example: https://forums.gentoo.org/viewtopic-t-996220-start-0.html

Motivation for this change

Things done

• Tested using sandboxing
  (nix.useSandbox on NixOS,
  or option build-use-sandbox in nix.conf
  on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • Linux
• Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Fits CONTRIBUTING.md.

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[mention-bot]

@spacekitteh, thanks for your PR! By analyzing the history of the files in this pull request, we identified @edolstra, @wkennington and @vcunat to be potential reviewers.

[spacekitteh]

Well it works

[spacekitteh]

@vcunat staging?

[spacekitteh]

(travis errord out 'cus of log length)

[viric]

I understand that "Some programs", in your case, means AOSP. Have you tested that the AOSP works for you with this patch? Because I can see that you tested that the patch does not break things, but I don't know if it fixes your problems with AOSP.

[spacekitteh]

It fixes one of many problems

[viric]

Does this change stdenv?

[spacekitteh]

I don't believe so, no. At least, it fetches stdenv rather than building it.

[viric]

I tested that it does not change stdenv. Good.

[vcunat]

It doesn't rebuild stdenv but it causes ~~10k job rebuilds just on x86_64-linux, which feels large enough to me.

[spacekitteh]

gdi

[vcunat]

Moved.

[vcunat]

The worst thing now is that such builds would have to be performed twice - once for master and again in staging (due to other mass-rebuild changes in there).

[viric]

Ah ok. Fine!