ci: run nix build on ubuntu and macos (#85)

* ci: run nix build on ubuntu and macos

* ci: use DeterminateSystems/nix-installer-action

* fix: wrong extension for mac

---------

Co-authored-by: pablo <p.lopez.lpz@gmail.com>

.github/workflows/ci.yml

@@ -55,19 +55,27 @@ jobs:
 
   nix-build:
     name: Nix Build
-    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        os: [ubuntu-latest, macOS-latest]
+    runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v6
         with:
           submodules: recursive
-      - uses: cachix/install-nix-action@v27
+      - uses: DeterminateSystems/nix-installer-action@v12
         with:
-          nix_path: nixpkgs=channel:nixos-unstable
           extra_nix_config: |
             experimental-features = nix-command flakes
+            nix-path = nixpkgs=channel:nixos-unstable
       - name: Build
         run: nix build ".?submodules=1#" --print-build-logs
       - name: Verify outputs
         run: |
-          test -f result/lib/liblogoschat.so
+          if [[ "$RUNNER_OS" == "macOS" ]]; then
+            ext=dylib
+          else
+            ext=so
+          fi
+          test -f result/lib/liblogoschat.$ext
           test -f result/include/liblogoschat.h