add cmake flag to ci

.github/workflows/ci.yaml

@@ -35,8 +35,27 @@ jobs:
         python -m pip install build pytest
       shell: bash
 
-    - name: Build DLL
+    - name: Install CMake (if needed)
+      if: runner.os == 'macOS' || runner.os == 'Windows'
       run: |
+        if [[ "$RUNNER_OS" == "Windows" ]]; then
+          choco install cmake --installargs 'ADD_CMAKE_TO_PATH=System' || exit 1
+        elif [[ "$RUNNER_OS" == "macOS" ]]; then
+          brew install cmake
+        fi
+      shell: bash
+
+    - name: Build DLL (Windows)
+      if: runner.os == 'Windows'
+      run: |
+        set CMAKE_ARGS="-DCMAKE_CXX_FLAGS=/openmp"
+        python -m pip install -e .
+      shell: bash
+
+    - name: Build (macOS)
+      if: runner.os == 'macOS'
+      run: |
+        CMAKE_ARGS="-DCMAKE_CXX_FLAGS=-fopenmp"
         python -m pip install -e .
       shell: bash