update flake build & CI

.github/workflows/build-linux.yml

@@ -18,8 +18,8 @@ jobs:
     runs-on: ubuntu-latest
     if: github.ref_name == 'main'
     steps:
-    - uses: actions/checkout@v3
-    - uses: cachix/install-nix-action@v22
+    - uses: actions/checkout@v4
+    - uses: cachix/install-nix-action@v27
 
     - name: Build
       working-directory: ${{github.workspace}}

.github/workflows/build-macos.yml

@@ -12,14 +12,17 @@ env:
 
 jobs:
   build:
+    strategy:
+      matrix:
+        os: [ macos-11, macos-12, macos-13 ]
     # The CMake configure and build commands are platform agnostic and should work equally well on Windows or Mac.
     # You can convert this to a matrix build if you need cross-platform coverage.
     # See: https://docs.github.com/en/free-pro-team@latest/actions/learn-github-actions/managing-complex-workflows#using-a-build-matrix
-    runs-on: macos-13
+    runs-on: ${{ matrix.os }} 
     if: github.ref_name == 'main'
     steps:
-    - uses: actions/checkout@v3
-    - uses: cachix/install-nix-action@v22
+    - uses: actions/checkout@v4
+    - uses: cachix/install-nix-action@v27
 
     - name: Build
       working-directory: ${{github.workspace}}

flake.nix

@@ -37,7 +37,7 @@
             ];
           };
           stdenv = pkgs.llvmPackages_18.stdenv;
-          operon = import ./operon.nix { inherit stdenv pkgs; };
+          operon = import ./operon.nix { inherit stdenv pkgs system; };
         in
         rec
         {

operon.nix

@@ -1,12 +1,17 @@
-{ stdenv, pkgs }:
-stdenv.mkDerivation {
+{ stdenv, pkgs, system }:
+stdenv.mkDerivation rec {
   name = "operon";
   src = ./.;
 
   enableShared = true;
 
+  cmakePreset = {
+    "x86_64-linux"   = "build-linux";
+    "aarch64-darwin" = "build-osx";
+  }."${system}"; 
+
   cmakeFlags = [
-    "--preset ${if pkgs.stdenv.hostPlatform.isx86_64 then "build-linux" else "build-osx"}"
+    "--preset ${cmakePreset}"
     "-DUSE_SINGLE_PRECISION=ON"
   ];
   cmakeBuildType = "Release";