can someone confirm if i'm going nutty or not?
https://github.com/NixOS/nixpkgs/blob/master/pkgs/top-level/all-packages.nix#L12603
should that `callPackage` not be `callPackages`?
context: https://github.com/NixOS/nixpkgs/blob/master/pkgs/development/libraries/libav/default.nix