[Factor-talk] Multiline shebangs (bug?)

[toastal <to...@po...>]

I want to use nix-shell which allows getting all tooling for a script
<https://nix.dev/manual/nix/2.34/command-ref/nix-shell.html#options>.
I’m trying to do

    #!/usr/bin/env nix-shell
    #!nix-shell ./env.nix -i factor
    USE: io
    IN: hello-world
    
    : hello ( -- ) "Hello world" print ;
    
    MAIN: hello

But when trying to exec my new script, I get

    2: #!nix-shell ./env.nix -i factor
              ^
    No word named '#!nix-shell' found in current vocabulary search path

The error makes sense if multiline shebangs aren’t supported (yet), but
I think this a bug & probably trivial fix.

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NOTE: I would prefer to use plain `nix-shell -i factor` but the factor
the binary ends up with a lower priority than `factor` from GNU
coreutlis — which means I have to do a hack with an ./env.nix file:

    { pkgs ? import <nixpkgs> { } }:
    
    let
        inherit (pkgs) lib factor-lang mkShellNoCC nix nixfmt;
    in
    mkShellNoCC {
        buildInputs = [
           (lib.hiPrio factor-lang.override { guiSupport = false; })
           nix
           nixfmt
        ];
    }