build: adopt xo-cmake macros as dependency

.github/workflows/cmake-single-platform.yml

@@ -22,18 +22,36 @@ jobs:
     steps:
     - uses: actions/checkout@v3
 
-    - name: Configure CMake
+    # ----------------------------------------------------------------
+
+    - name: Clone xo-cmake
+      uses: actions/checkout@v3
+      with:
+        repository: Rconybea/xo-cmake
+        path: repo/xo-cmake
+
+    - name: Configure xo-cmake
+      run: cmake -B ${{github.workspace}}/build_xo-cmake -DCMAKE_INSTALL_PREFIX=${{github.workspace}}/local repo/xo-cmake
+
+    - name: Build xo-cmake (trivial)
+      run: cmake --build ${{github.workspace}}/build_xo-cmake --config ${{env.BUILD_TYPE}}
+
+    - name: Install xo-cmake
+      run: cmake --install ${{github.workspace}}/build_xo-cmake
+
+    # ----------------------------------------------------------------
+
+    - name: Configure self (subsys)
       # Configure CMake in a 'build' subdirectory. `CMAKE_BUILD_TYPE` is only required if you are using a single-configuration generator such as make.
       # See https://cmake.org/cmake/help/latest/variable/CMAKE_BUILD_TYPE.html?highlight=cmake_build_type
-      run: cmake -B ${{github.workspace}}/build -DCMAKE_BUILD_TYPE=${{env.BUILD_TYPE}}
+      run: cmake -B ${{github.workspace}}/build -DCMAKE_MODULE_PATH=${{github.workspace}}/local/share/cmake -DCMAKE_BUILD_TYPE=${{env.BUILD_TYPE}}
 
-    - name: Build
+    - name: Build self (subsys)
       # Build your program with the given configuration
       run: cmake --build ${{github.workspace}}/build --config ${{env.BUILD_TYPE}}
 
-    - name: Test
+    - name: Test self (subsys)
       working-directory: ${{github.workspace}}/build
       # Execute tests defined by the CMake configuration.
       # See https://cmake.org/cmake/help/latest/manual/ctest.1.html for more detail
       run: ctest -C ${{env.BUILD_TYPE}}
-