libyaml-cpp: Fix wrong paths in pkg-config .pc file.

[nh2]

Motivation for this change

Same as in #71669 and #81091 and 029c3f9.

See #144170 for the general issue.

Before this fix:

NIX_PATH=nixpkgs=. nix-shell -p libyamlcpp -p pkg-config --run 'pkg-config --cflags yaml-cpp'
-I/nix/store/bq106wng1cqk8r4y1y7yh5h7cz49jxpv-libyaml-cpp-0.7.0//nix/store/bq106wng1cqk8r4y1y7yh5h7cz49jxpv-libyaml-cpp-0.7.0/include

With this fix, the path is correct:

NIX_PATH=nixpkgs=. nix-shell -p libyamlcpp -p pkg-config --run 'pkg-config --cflags yaml-cpp'
-I/nix/store/9hwyd6im206isapba0i8gyc5i3g1df2j-libyaml-cpp-0.7.0/include

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandbox = true set in nix.conf? (See Nix manual)
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all packages 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/)
• 21.11 Release Notes (or backporting 21.05 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
• Fits CONTRIBUTING.md.

[r-burns]

I would suggest filing an upstream issue for this and pointing them to https://github.com/jtojnar/cmake-snips#concatenating-paths-when-building-pkg-config-files

[r-burns]

I opened an upstream PR for this: jbeder/yaml-cpp#1058

[SuperSandro2000]

Can we fetch the patch instead?

[nh2]

Can we fetch the patch instead?

Done.

[r-burns]

Builds on x86_64-linux. Thanks!

[nh2]

Btw, it would probably make sense to rename libyamlcpp to yaml-cpp in nixpkgs, and add an alias to the old one.

[r-burns]

Repology agrees: https://repology.org/project/yaml-cpp/versions