Install libcap-dev in the CI so python-prctl can build

.github/workflows/Testbase.yml

@@ -25,7 +25,7 @@ jobs:
           python-version: ${{ inputs.python }}
       - name: Install package
         run: |
-          sudo apt install libxkbcommon-x11-0 libxcb-icccm4 libxcb-image0 libxcb-keysyms1 libxcb-randr0 libxcb-render-util0 libxcb-xinerama0 libxcb-xfixes0 x11-utils
+          sudo apt install libxkbcommon-x11-0 libxcb-icccm4 libxcb-image0 libxcb-keysyms1 libxcb-randr0 libxcb-render-util0 libxcb-xinerama0 libxcb-xfixes0 x11-utils libcap-dev
           python -m pip install --upgrade pip
           export QT_DEBUG_PLUGINS=1
           pip install flake8 pytest pytest-cov pytest-qt pytest-xdist pytest-xvfb setuptools wheel numpy h5py ${{ inputs.qt5 }} toml

.github/workflows/compatibility.yml

@@ -43,6 +43,11 @@ jobs:
         with:
           python-version: ${{ matrix.python-version }}
 
+      # python-prctl (needed by picamera2) is compiled against the libcap headers
+      - name: Install libcap headers (Linux)
+        if: runner.os == 'Linux'
+        run: sudo apt update && sudo apt install -y libcap-dev
+
       - name: Install dependencies
         run: |
           python -m pip install --upgrade pip