GHA: Add ppa:ubuntu-toolchain-r/test for gcc-10

.github/workflows/build-linux.yml

@@ -85,7 +85,8 @@ jobs:
           apt-get update
           apt-get install -y build-essential git wget curl sudo unzip zip openjdk-11-jdk autoconf libfreetype6-dev libcups2-dev libx11-dev libxext-dev libxrender-dev libxrandr-dev libxtst-dev libxt-dev libasound2-dev libffi-dev file binutils libfontconfig-dev
           # If we really need gcc-10, we can get it from this PPA:
-          #sudo add-apt-repository ppa:ubuntu-toolchain-r/test
+          apt-get install -y software-properties-common
+          sudo add-apt-repository ppa:ubuntu-toolchain-r/test
 
       - name: 'Checkout the JDK source'
         uses: actions/checkout@v3
@@ -123,7 +124,7 @@ jobs:
           fi
           sudo apt-get update
           sudo apt-get install --only-upgrade apt
-          sudo apt-get install gcc-${{ inputs.gcc-major-version }}${{ inputs.gcc-package-suffix }} g++-${{ inputs.gcc-major-version }}${{ inputs.gcc-package-suffix }} libxrandr-dev${{ steps.arch.outputs.suffix }} libxtst-dev${{ steps.arch.outputs.suffix }} libcups2-dev${{ steps.arch.outputs.suffix }} libasound2-dev${{ steps.arch.outputs.suffix }} ${{ inputs.apt-extra-packages }}
+          sudo apt-get install -y gcc-${{ inputs.gcc-major-version }}${{ inputs.gcc-package-suffix }} g++-${{ inputs.gcc-major-version }}${{ inputs.gcc-package-suffix }} libxrandr-dev${{ steps.arch.outputs.suffix }} libxtst-dev${{ steps.arch.outputs.suffix }} libcups2-dev${{ steps.arch.outputs.suffix }} libasound2-dev${{ steps.arch.outputs.suffix }} ${{ inputs.apt-extra-packages }}
           sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-${{ inputs.gcc-major-version }} 100 --slave /usr/bin/g++ g++ /usr/bin/g++-${{ inputs.gcc-major-version }}
 
       - name: 'Configure'