While this can be made to compile on darwin:
- override cairo with x11Support
- fixup dylib paths in the binary
- add explicit libXrender for darwin
the app crashes anyway on floating point exception and doesn't do anything.
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.
