pr_build: Get GCC 13 on Ubuntu using the ppa:ubuntu-toolchain-r/test.

.github/workflows/pr_build.yml

@@ -184,12 +184,21 @@ jobs:
       run: |
         if [[ "${{ matrix.os }}" =~ "Ubuntu" || "${{ matrix.os }}" =~ "Debian" ]]; then
 
+          echo "Adding Toolchain test PPA"
+          add-apt-repository ppa:ubuntu-toolchain-r/test
+
           echo "Updating apt repository index"
           sudo apt update || exit 1
 
           echo "Installing apt packages"
           sudo apt install -y ${{ matrix.apt-dependencies }} || exit 1
 
+          echo "Installing gcc-13"
+          sudo apt install -y gcc-13 g++-13 || exit 1
+
+          # Set GCC 13 as default
+          update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-13 100 --slave /usr/bin/g++ g++ /usr/bin/g++-13 --slave /usr/bin/gcov gcov /usr/bin/gcov-13
+
         else # macOS
           echo "Downloading MacOSX10.12 SDK.."
           curl --progress-bar -L -o macOS_SDK10.12.4.tar.xz "https://data.moto9000.moe/overte_packages/macOS_SDK10.12.4.tar.xz" || exit 1