Set up a development shell with Nix.

Just for local development; no one's shipping anything with this thing.

.envrc

@@ -0,0 +1,3 @@
+#!/usr/bin/env bash
+
+source_env_if_exists ./.envrc.local

.envrc.local

@@ -0,0 +1,5 @@
+#!/usr/bin/env bash
+
+use flake
+
+source_env ../.envrc

.github/workflows/nix.yaml

@@ -0,0 +1,20 @@
+name: test Nix support
+
+on: push
+
+jobs:
+  evaluate-nix-shell:
+    name: Evaluate the Nix shell
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout 🛎️
+        uses: actions/checkout@v3
+
+      - name: Install Nix ❄
+        uses: DeterminateSystems/nix-installer-action@v4
+
+      - name: Run the Magic Nix Cache 🔌
+        uses: DeterminateSystems/magic-nix-cache-action@v2
+
+      - name: Evaluate the Nix shell
+        run: nix develop -c "true"

.gitignore

@@ -1 +1,5 @@
+# Rust
 /target
+
+# direnv
+/.direnv

flake.nix

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+{
+  description = "ndc-sdk";
+
+  inputs = {
+    flake-utils.url = github:numtide/flake-utils;
+    nixpkgs.url = github:NixOS/nixpkgs/master;
+  };
+
+  outputs =
+    { self
+    , flake-utils
+    , nixpkgs
+    }:
+    flake-utils.lib.eachDefaultSystem (system:
+    let
+      pkgs = import nixpkgs { inherit system; };
+    in
+    {
+      devShells.default = pkgs.mkShell {
+        nativeBuildInputs = [
+          pkgs.cargo
+          pkgs.cargo-edit
+          pkgs.cargo-machete
+          pkgs.clippy
+          pkgs.rust-analyzer
+          pkgs.rustPlatform.rustcSrc
+          pkgs.rustc
+          pkgs.rustfmt
+        ];
+
+        buildInputs = pkgs.lib.optionals pkgs.stdenv.isDarwin [
+          pkgs.darwin.apple_sdk.frameworks.Security
+          pkgs.libiconv
+        ];
+      };
+
+      formatter = pkgs.nixpkgs-fmt;
+    });
+}