ci: use ninja but only on windows

.github/workflows/ci.yml

@@ -150,6 +150,16 @@ jobs:
         curl -fLOSs --retry 3 http://olivevideoeditor.org/deps/crashpad-$DEP_SUFFIX
         $EXTRACT_TOOL crashpad-$DEP_SUFFIX
 
+    - name: Configure CMake
+      shell: bash
+      working-directory: ${{ runner.workspace }}/build
+      run: |
+        PATH=$GITHUB_WORKSPACE:$PATH \
+        OPENEXR_ROOT=$GITHUB_WORKSPACE \
+        FFMPEG_ROOT=$GITHUB_WORKSPACE \
+          cmake $GITHUB_WORKSPACE -DCMAKE_BUILD_TYPE=${{ matrix.build-type }} -G Ninja
+      if: matrix.os == 'windows-latest'
+
     - name: Configure CMake
       shell: bash
       working-directory: ${{ runner.workspace }}/build
@@ -158,6 +168,7 @@ jobs:
         OPENEXR_ROOT=$GITHUB_WORKSPACE \
         FFMPEG_ROOT=$GITHUB_WORKSPACE \
           cmake $GITHUB_WORKSPACE -DCMAKE_BUILD_TYPE=${{ matrix.build-type }}
+      if: matrix.os == 'macos-latest'
 
     - name: Build
       working-directory: ${{ runner.workspace }}/build