Add bazel builds and test to Github-CI.

.github/workflows/build.yml

@@ -39,3 +39,26 @@ jobs:
         - name: Test
           shell: bash
           run: cd build && ctest --output-on-failure
+
+  bz-build:
+      strategy:
+        matrix:
+          os: [ubuntu-latest, windows-latest, macos-latest]
+      runs-on: ${{ matrix.os }}
+      steps:
+        - uses: actions/checkout@v2
+
+        - name: Build
+          shell: bash
+          run: |
+            cd "${{ github.workspace }}"
+            bazel build '//:yaml-cpp'
+
+        - name: Test
+          shell: bash
+          run: |
+            cd "${{ github.workspace }}"
+            # For some reason 'bazel test //test:test' gets the first / stripped on windows in CI.
+            # Therefore use this ugly version, which is working on all platforms.
+            bazel test test
+

BUILD.bazel

@@ -1,6 +1,6 @@
 yaml_cpp_defines = select({
     # On Windows, ensure static linking is used.
-    "@envoy//bazel:windows_x86_64": ["YAML_CPP_STATIC_DEFINE", "YAML_CPP_NO_CONTRIB"],
+    "@platforms//os:windows": ["YAML_CPP_STATIC_DEFINE", "YAML_CPP_NO_CONTRIB"],
     "//conditions:default": [],
 })