More completely fix recursive nix, unbreak tests
More completely fix recursive nix, unbreak tests

See:
https://github.com/NixOS/nix/commit/88b5d0c8e89afefbc547b6243c5aa5a3ec8176e9#commitcomment-27406365

shlevy/nix,layus/nix,NixOS/nix,rycee/nix,zimbatm/nix,dezgeg/nix,dezgeg/nix,layus/nix,vcunat/nix,dtzWill/nix,ehmry/nix,vcunat/nix,NixOS/nix,pikajude/nix,ehmry/nix,rycee/nix,dezgeg/nix,ehmry/nix,ehmry/nix,peti/nix,dtzWill/nix,shlevy/nix,peti/nix,zimbatm/nix,vcunat/nix,vcunat/nix,NixOS/nix,peti/nix,shlevy/nix,ehmry/nix,layus/nix,dezgeg/nix,dezgeg/nix,NixOS/nix,dtzWill/nix,shlevy/nix,ehmry/nix,NixOS/nix,shlevy/nix,dtzWill/nix,pikajude/nix,layus/nix,rycee/nix,rycee/nix,layus/nix,peti/nix,zimbatm/nix,rycee/nix,dtzWill/nix,peti/nix,pikajude/nix,zimbatm/nix