Also test with clang.

Author: bangerth

.github/workflows/SampleFlow-test.yml

@@ -10,15 +10,15 @@ on:
 jobs:
   build:
 
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-24.04
 
     steps:
     - uses: actions/checkout@v2
     - name: install dependencies
       run: |
         pushd .
         cd $HOME
-        sudo apt-get install doxygen graphviz libboost-all-dev numdiff -y
+        sudo apt-get install -y doxygen graphviz libboost-all-dev numdiff clang libc++-dev libc++abi-dev
         doxygen --version
         git clone https://gitlab.com/libeigen/eigen.git
         mkdir ./eigen-build
@@ -27,15 +27,25 @@ jobs:
         cmake ../eigen -DCMAKE_INSTALL_PREFIX=$HOME/eigen-install
         make install
         popd
-    - name: cmake
+    - name: cmake-gcc
       run: |
            mkdir build-gcc
            cd build-gcc
            cmake -DEIGEN_DIR="$HOME/eigen-install" -DCMAKE_BUILD_TYPE=Debug ..
-    - name: ctest
+    - name: ctest-gcc
       run: |
            cd build-gcc
            ctest --output-on-failure -j2
+    - name: cmake-clang
+      run: |
+           mkdir build-clang
+           cd build-clang
+           export CXX=clang++
+           cmake -DEIGEN_DIR="$HOME/eigen-install" -DCMAKE_BUILD_TYPE=Debug ..
+    - name: ctest-clang
+      run: |
+           cd build-clang
+           ctest --output-on-failure -j2
     - name: doc
       run: |
            cd build-gcc