Switch GCC-12 CI job to GCC 13

This is to test an even more recent GCC release. Also, disable doc and
package building attempts as those are already covered in other CI jobs.

Author: tautschnig

.github/workflows/pull-request-checks.yaml

@@ -391,7 +391,7 @@ jobs:
         run: cd build; ctest . -V -L CORE -j2
 
   # This job takes approximately 26 to 46 minutes
-  check-ubuntu-22_04-cmake-gcc-12:
+  check-ubuntu-22_04-cmake-gcc-13:
     runs-on: ubuntu-22.04
     steps:
       - uses: actions/checkout@v3
@@ -404,7 +404,13 @@ jobs:
           DEBIAN_FRONTEND: noninteractive
         run: |
           sudo apt-get update
-          sudo apt-get install --no-install-recommends -yq cmake ninja-build gcc-12 gdb g++-12 maven flex bison libxml2-utils dpkg-dev ccache doxygen z3
+          sudo apt-get install --no-install-recommends -yq cmake ninja-build gcc-13 gdb g++-13 maven flex bison libxml2-utils dpkg-dev ccache doxygen z3
+          # Update symlinks so that any use of gcc (including our regression
+          # tests) will use GCC 13.
+          sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-13 110 \
+            --slave /usr/bin/g++ g++ /usr/bin/g++-13 \
+            --slave /usr/bin/gcov gcov /usr/bin/gcov-13
+          sudo ln -sf cpp-13 /usr/bin/cpp
       - name: Confirm z3 solver is available and log the version installed
         run: z3 --version
       - name: Download cvc-5 from the releases page and make sure it can be deployed
@@ -417,29 +423,22 @@ jobs:
         uses: actions/cache@v3
         with:
           path: .ccache
-          key: ${{ runner.os }}-22.04-Release-gcc-12-${{ github.ref }}-${{ github.sha }}-PR
+          key: ${{ runner.os }}-22.04-Release-gcc-13-${{ github.ref }}-${{ github.sha }}-PR
           restore-keys: |
-            ${{ runner.os }}-22.04-Release-gcc-12-${{ github.ref }}
-            ${{ runner.os }}-22.04-Release-gcc-12
+            ${{ runner.os }}-22.04-Release-gcc-13-${{ github.ref }}
+            ${{ runner.os }}-22.04-Release-gcc-13
       - name: ccache environment
         run: |
           echo "CCACHE_BASEDIR=$PWD" >> $GITHUB_ENV
           echo "CCACHE_DIR=$PWD/.ccache" >> $GITHUB_ENV
       - name: Configure using CMake
-        run: cmake -S . -Bbuild -G Ninja -DCMAKE_BUILD_TYPE=Release -DCMAKE_C_COMPILER=/usr/bin/gcc-12 -DCMAKE_CXX_COMPILER=/usr/bin/g++-12
-      - name: Check that doc task works
-        run: ninja -C build doc
+        run: cmake -S . -Bbuild -G Ninja -DCMAKE_BUILD_TYPE=Release
       - name: Zero ccache stats and limit in size
         run: ccache -z --max-size=500M
       - name: Build with Ninja
         run: ninja -C build -j2
       - name: Print ccache stats
         run: ccache -s
-      - name: Check if package building works
-        run: |
-          cd build
-          ninja package
-          ls *.deb
       - name: Run tests
         run: cd build; ctest . -V -L CORE -j2