Add Mac OS X builds to GitHub Actions

Author: ccawley2011

.github/workflows/ci.yml

@@ -31,6 +31,31 @@ jobs:
         name: arcem-linux-${{ matrix.linux.system }}
         path: ./build/arcem
 
+  build-macosx:
+    name: Mac OS X (${{ matrix.macosx.system }})
+    runs-on: macos-latest
+
+    strategy:
+      matrix:
+        macosx:
+        - { system: X,    brew-packages: xquartz      }
+        - { system: SDL1, brew-packages: sdl12-compat }
+        - { system: SDL2, brew-packages: sdl2         }
+
+    steps:
+    - uses: actions/checkout@v3
+    - name: Install dependencies
+      if: ${{ matrix.macosx.brew-packages != '' }}
+      run: brew install ${{ matrix.macosx.brew-packages }}
+    - name: Configure
+      run: cmake -B build/ -DCMAKE_BUILD_TYPE=${{env.BUILD_TYPE}} -DSYSTEM=${{ matrix.macosx.system }} .
+    - name: Build
+      run: cmake --build build/ --config ${{env.BUILD_TYPE}} --parallel
+    - uses: actions/upload-artifact@v4
+      with:
+        name: arcem-macosx-${{ matrix.macosx.system }}
+        path: ./build/ArcEm.app
+
   build-msvc:
     name: Windows (MSVC ${{ matrix.msvc.platform }})
     runs-on: windows-latest