I'm trying to build gateware using a fork from the latest commit of artiq, however, the old gateware build instructions at https://m-labs.hk/artiq/manual-beta/developing.html are no longer correct. Following the instructions yields the following:
$ nix-shell -I artiqSrc=~/scratch/artiq ~/scratch/nix-scripts/artiq-fast/shell-dev.nix
trace: For ARTIQ 7+, use 'nix develop' on the flake instead.
error: assertion (((pkgs).lib.asserts.assertMsg (! (((pkgs).lib.strings.versionAtLeast (artiqpkgs).artiq.version) "7.0"))) "For ARTIQ 7+, use 'nix develop' on the flake instead.") failed at /home/rabi/scratch/nix-scripts/artiq-fast/shell-dev.nix:7:3
The error message would appear helpful, however, the latest stable version of nix has no "develop" command, and besides I'm not 100% on what the "flake" is - is it
flake.nix in the main artiq repository?
$ nix --version
nix (Nix) 2.3.15
$ nix develop
error: 'develop' is not a recognised command
Try 'nix --help' for more information.
Do I need to install nix from source to get access to nix develop? What else do I need to do to build gateware at the current state of ARTIQ 7?
This is all under Ubuntu 20.04.3 LTS.