fish: Add fishEnvPreInit option

This new option allows for replacing the sourcing of
/etc/fish/nixos-env-preinit.fish with another file, optionally passing
it through `fenv`. The idea here is that non-NixOS users can do
something like

    fish.override {
      fishEnvPreInit = sourceBash:
        sourceBash "${nix}/etc/profile.d/nix-daemon.sh";
    }

and this will set up their shell environment for Nix just as though they
were running NixOS.

0 files changed, 0 insertions, 0 deletions