Install fails on Apple DTK

[shepting]

Describe the bug
The install script fails on the Apple DTK (Developer Transition Kit). This is on macOS 11 Beta 8.

This isn't an issue due to Big Sur, as that has already been fixed (#3853).

Steps To Reproduce

1. Open Terminal.app
2. Paste curl -L https://nixos.org/nix/install | sh
3. See error

Expected behavior
I expected the install to begin on my DTK. Alternately, I would have expected at least an informative message explaining that "We don't yet support Nix on macOS using the ARM architecture...", etc.

nix-env --version output
zsh: command not found: nix-env

[shepting]

It looks like the more full-featured request for support of ARM Macs is here: #3853

This bug could be solved with a simple log message explaining that support is being worked on.

[edolstra]

Nix on Apple Silicon is not currently supported. Not sure if anybody is actively working on it at the moment.

[Kloenk]

I would like to work on it, but don't have an DTK, and I'm also a student, so only limited time available.

[abathur]

It seems like a win to at least fix the error message here.

@shepting Can you confirm what /bin/sh -c "uname -m" returns? (hopefully arm64?)

[thefloweringash]

It returns arm64 for me. We should use the x86_64 binary until we have we have native support.

[domenkozar]

@Kloenk see NixOS/nixpkgs#95903 (comment)

[Kloenk]

Thanks. I ordered the Mac book Pro, so will have one shortly. My exams are soon, so probably not to bad to just wait, and then have time with own hardware.

[angerman]

@abathur's change 4864df6 does work.

(assuming a patched install script as per the change above)

sh <(curl -L https://nixos.org/nix/install) --darwin-use-unencrypted-nix-store-volume

will successfully install an x86_64 nix, that works via rosetta.

nix-build -I nixpkgs=https://github.com/nixos/nixpkgs/archive/master.tar.gz -E '(import <nixpkgs> {}).hello.overrideAttrs (_: { HELLO = "WORLD"; })'

will then build a working hello executable.

➜  ~ nix-build -I nixpkgs=https://github.com/nixos/nixpkgs/archive/master.tar.gz -E '(import <nixpkgs> {}).hello.overrideAttrs (_: { HELLO = "WORLD"; })'
➜  ~ file ./result/bin/hello
./result/bin/hello: Mach-O 64-bit executable x86_64
➜  ~ ./result/bin/hello
Hello, world!
➜  ~ echo $(uname -s).$(uname -m)
Darwin.arm64