I've upstreamed these patches in NixOS/nixpkgs#144409, which means we no
longer have to build the kernel every time we update just to get
bluetooth working 🎉
While these changes have landed in master, they haven't been back-ported
to 21.05. They will be available via 21.11, which I'm currently testing
(along with this commit) by setting my `nixos` channel to the necessary
nixpkgs pre-release branch, e.g.
```bash
sudo nix-channel --remove nixos
sudo nix-channel --add https://github.com/NixOS/nixpkgs/archive/release-21.11.tar.gz nixos
sudo nix-channel --update nixos
```
*Note that if you use the above branch like I am, you might miss the
cache on some pkgs and spend even longer building those (looking at you
libreoffice).*
As of writing this PR, the current kernel is 5.15.4 and all seems to be
working well.
1794de7d78