nix: Do not rely on /bin/bash or /usr/bin/env being present on nix
nix: Do not rely on /bin/bash or /usr/bin/env being present on nix

This works around https://github.com/NixOS/nixpkgs/issues/6227

It looks like I can’t run the “portable script” that I am creating in
order to ship it in my own nix-build :-(

entropia/tip-toi-reveng,entropia/tip-toi-reveng,entropia/tip-toi-reveng,entropia/tip-toi-reveng,entropia/tip-toi-reveng,entropia/tip-toi-reveng