a6afdbb70b
This fixes a regression from 993baa587c4 which requires networking.hostName to be a valid DNS label [0]. Unfortunately we missed the fact that the hostnames may also be empty, if the user wants to obtain it from a DHCP server. This is even required by a few modules/images (e.g. Amazon EC2, Azure, and Google Compute). [0]: https://github.com/NixOS/nixpkgs/pull/76542#issuecomment-638138666
*** NixOS *** NixOS is a Linux distribution based on the purely functional package management system Nix. More information can be found at https://nixos.org/nixos and in the manual in doc/manual.