install xcode

Author: thejohnfreeman

.github/workflows/cupcake.yml

@@ -106,6 +106,11 @@ jobs:
         uses: jwlawson/actions-setup-cmake@v2
         with:
           cmake-version: ${{ matrix.cmake }}
+      - name: install XCode on macOS
+        if: startsWith(matrix.platform, 'macos')
+        uses: maxim-lobanov/setup-xcode@v1
+        with:
+          xcode-version: '15.3'
       - name: install Ninja on Linux
         if: matrix.generator == 'Ninja' && startsWith(matrix.platform, 'ubuntu')
         run: sudo apt install ninja-build