nixpkgs' pkgs.writers replaces nix-writers' top-level writeDash,
writeDashBin, writeBashBin and write (now linkFarm).

Nothing uses them; red-host reads the clan vars secretLocation directly.

Copied from stockholm krebs/3modules/realwallpaper.nix (cc283503); the
wallpaper generator comes from stockholm's packages output instead of
its overlay.

Copied from stockholm krebs/3modules/reaktor2.nix (cc283503). The bot
itself goes to pkgs/reaktor2 (with blessings, which nixpkgs lacks),
since stockholm's packages output does not include it.

Copied from stockholm krebs/3modules/htgen.nix (cc283503), so it no
longer needs pkgs.htgen from the stockholm overlay.

barnacle's hosts block only had kartei.extraHosts, so starkstrom.r and
acheron.r did not resolve there. self.retiolum now exposes extraHosts
(v4v6/v6only) rendered like kartei's, and barnacle appends it.