flake: expose some packages to be built by github ci

.github/workflows/cachix.yml

@@ -1,12 +1,12 @@
-name: Check
+name: CI
 
 on:
   push:
   workflow_dispatch:
 
 jobs:
-  linux:
+  check:
-    name: Evaluate and build flake
+    name: Check flake
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2.3.4
@@ -19,3 +19,37 @@ jobs:
           name: lava
           authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
       - run: nix flake check --keep-going --verbose
+  build:
+    name: Build linux-lava for x86_64-linux
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2.3.4
+      - uses: cachix/install-nix-action@v13
+        with:
+          install_url: https://github.com/numtide/nix-unstable-installer/releases/download/nix-2.5pre20211026_5667822/install
+          extra_nix_config: experimental-features = nix-command flakes
+      - uses: cachix/cachix-action@v10
+        with:
+          name: lava
+          authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
+      - run: nix build -L .#linux-lava
+
+  build-nix:
+    runs-on: ubuntu-latest
+    name: Build nixUnstable for aarch64-linux
+    steps:
+      - uses: actions/checkout@v2.1.0
+      - uses: dbhi/qus/action@main
+        with:
+          targets: arm aarch64
+      - uses: cachix/install-nix-action@v13
+        with:
+          install_url: https://github.com/numtide/nix-unstable-installer/releases/download/nix-2.5pre20211026_5667822/install
+          extra_nix_config: |
+            extra-platforms = aarch64-linux arm-linux
+            experimental-features = nix-command flakes
+      - uses: cachix/cachix-action@v10
+        with:
+          name: lava
+          authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
+      - run: nix build -L .#packages.aarch64-linux.nixUnstable

flake.nix

@@ -88,6 +88,28 @@
 
       nixosConfigurations."caramel" = mkSystem nixpkgs-porcupine "caramel" "aarch64-linux" false;
 
+      packages."x86_64-linux" =
+        let
+          pkgs = import nixpkgs {
+            inherit overlays;
+            system = "x86_64-linux";
+          };
+        in
+        {
+          inherit (pkgs.me) linux-lava;
+        };
+
+      packages."aarch64-linux" =
+        let
+          pkgs = import nixpkgs-porcupine {
+            inherit overlays;
+            system = "aarch64-linux";
+          };
+        in
+        {
+          inherit (pkgs) nixUnstable;
+        };
+
       # TODO: currently broken
       # devShells.x86_64-linux = pkgs.callPackage ./shells { inherit inputs; };
     };