flake.nix: use zig 0.12.0 from zig-overlay.

.github/workflows/zig.yml

@@ -1,33 +1,15 @@
-name: Zig
+on: [push, pull_request]
 
-on:
-  push:
-  pull_request:
-  schedule:
-    - cron: "0 0 * * *"
+name: build
 
 jobs:
-  test:
-    strategy:
-      matrix:
-        os: [ubuntu-latest, macos-latest, windows-latest]
-    runs-on: ${{matrix.os}}
-    steps:
-      - uses: actions/checkout@v2
-        with:
-          submodules: recursive
-      - uses: goto-bus-stop/setup-zig@v1
-        with:
-          version: master
-      - run: zig build
-      - run: zig build test
-  lint:
+  zig:
+    name: Build and test
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
-        with:
-          submodules: recursive
-      - uses: goto-bus-stop/setup-zig@v1
-        with:
-          version: master
-      - run: zig fmt --check build.zig src/*.zig
+      - 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
+      - run: nix flake check -L

flake.nix

@@ -0,0 +1,40 @@
+{
+  inputs = {
+    zig = {
+      url = github:mitchellh/zig-overlay;
+      inputs.nixpkgs.follows = "nixpkgs";
+      inputs.flake-utils.follows = "flake-utils";
+    };
+  };
+
+  outputs = {
+    self,
+    nixpkgs,
+    flake-utils,
+    zig,
+  }:
+    flake-utils.lib.eachDefaultSystem (system: let
+      pkgs = nixpkgs.legacyPackages.${system};
+      inherit (pkgs) lib;
+    in rec {
+      packages.default = pkgs.stdenv.mkDerivation {
+        name = "htmlentities.zig-build";
+
+        src = ./.;
+
+        nativeBuildInputs = [
+          zig.packages.${system}."0.12.0"
+        ];
+
+        buildPhase = ''
+          export ZIG_GLOBAL_CACHE_DIR="$TMPDIR/zig"
+          zig build test
+          touch $out
+        '';
+
+        dontInstall = true;
+      };
+
+      formatter = pkgs.alejandra;
+    });
+}