Added suggested macOS fix and fixed data.table package.
Added suggested macOS fix and fixed data.table package.

`data.table` had a `postInstall` step to rename `data.table.so` to `datatable.so`, but after the package bump the file was already called `datatable.so` and `mv` command would fail.

NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs