continuation of #109595
pkgconfig was aliased in 2018, however, it remained in
all-packages.nix due to its wide usage. This cleans
up the remaining references to pkgs.pkgsconfig and
moves the entry to aliases.nix.
python3Packages.pkgconfig remained unchanged because
it's the canonical name of the upstream package
on pypi.
Semi-automatic update generated by https://github.com/ryantm/nix-update tools. These checks were done:
- built on NixOS
- Warning: no binary found that responded to help or version flags. (This warning appears even if the package isn't expected to have binaries.)
- found 0.4.3 with grep in /nix/store/ksrz74w4gzxb2mf8yb3f3i67i80cr93v-libfixposix-0.4.3
- directory tree listing: https://gist.github.com/ddc89b6def68fbc70c046bfdaa1c02b8
