bandwidth: fix build on darwin, fix license, adopt (#101522)
bandwidth: fix build on darwin, fix license, adopt (#101522)

Cleaned up rules a bit for platform-independent building.
License was incorrectly listed as MIT, it is actually GPL2+.
Taking on maintainership as it appears to be orphaned.
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