add multiplatform building, to be sure

.github/workflows/cmake.yml

@@ -12,26 +12,28 @@ env:
 
 jobs:
   build:
-    # 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: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+          os: [ubuntu-latest, macos-latest, windows-latest]
+          include:
+            - os: macos-latest
+              extra_cmake_config_flags: -DCMAKE_OSX_ARCHITECTURES="x86_64;arm64" # universal. arm and intel
+            - os: windows-latest
+              extra_cmake_config_flags: -DCMAKE_GENERATOR_PLATFORM=x64 # make sure it's x64
+
+    runs-on: ${{ matrix.os }}
 
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
 
     - name: Configure CMake
-      # Configure CMake in a 'build' subdirectory. `CMAKE_BUILD_TYPE` is only required if you are using a single-configuration generator such as make.
-      # See https://cmake.org/cmake/help/latest/variable/CMAKE_BUILD_TYPE.html?highlight=cmake_build_type
-      run: cmake -B ${{github.workspace}}/build -DCMAKE_BUILD_TYPE=${{env.BUILD_TYPE}}
+      run: cmake -B ${{github.workspace}}/build -DCMAKE_BUILD_TYPE=${{env.BUILD_TYPE}}  ${{ matrix.extra_cmake_config_flags}}
 
-    - name: Build
-      # Build your program with the given configuration
+    - name: Build with CMake
       run: cmake --build ${{github.workspace}}/build --config ${{env.BUILD_TYPE}}
 
     - name: Test
       working-directory: ${{github.workspace}}/build
-      # Execute tests defined by the CMake configuration.
-      # See https://cmake.org/cmake/help/latest/manual/ctest.1.html for more detail
       run: ctest -C ${{env.BUILD_TYPE}}