Add mac/windows sample builds

.github/workflows/sample_build.yml

@@ -10,10 +10,11 @@ on:
 
 jobs:
   build_wheels:
-    name: Sample build [${{ matrix.result }}]
+    name: Sample build [${{ matrix.os }},${{ matrix.result }}]
-    runs-on: ubuntu-18.04
+    runs-on: ${{ matrix.os }}
     strategy:
       matrix:
+        os: [ubuntu-18.04, windows-latest, macos-latest]
         result: [success, failure]
 
     steps:
@@ -28,6 +29,11 @@ jobs:
         run: |
           python -m pip install -r requirements-dev.txt
 
+      - name: Install Visual C++ for Python 2.7
+        if: runner.os == 'Windows'
+        run: |
+          choco install vcpython27 -f -y
+
       - name: Generate sample project
         run: |
           if $should_fail; then