github: Test installing and running on macOS too

.github/workflows/build.yml

@@ -4,7 +4,7 @@ on:
   pull_request:
 
 jobs:
-  test-msvc-wine:
+  test-msvc-wine-linux:
     runs-on: ubuntu-latest
     steps:
       - name: Install prerequisites
@@ -24,6 +24,26 @@ jobs:
       # Intentionally not storing any artifacts with the downloaded tools;
       # the installed files aren't redistributable!
 
+  test-msvc-wine-macos:
+    runs-on: macos-latest
+    steps:
+      - name: Install prerequisites
+        run: |
+          brew install wine-stable msitools
+          wine64 wineboot
+      - uses: actions/checkout@v3
+      - name: Download MSVC
+        run: |
+          ./vsdownload.py --accept-license --dest $(pwd)/msvc
+          ./install.sh $(pwd)/msvc
+      - name: Test using the installed tools
+        run: |
+          for arch in x86 x64 arm arm64; do
+              ./msvc/bin/$arch/cl hello.c -Fehello-$arch.exe
+          done
+      # Intentionally not storing any artifacts with the downloaded tools;
+      # the installed files aren't redistributable!
+
   test-clang-lld:
     # Ubuntu 22.04 comes with Clang/LLD 14; at least 13 is required for providing
     # __guard_eh_cont_table and __guard_eh_cont_count which are required with