Install kscreenlocker-dev by entering the following commands in the terminal:
sudo apt update sudo apt install kscreenlocker-dev
Description:
Development files for kscreenlocker
Library and components for secure lock screen architecture. . This package contains development files for kscreenlocker.
Homepage: https://projects.kde.org/kscreenlocker
Version: 5.12.4-0ubuntu1
Section: universe/libdevel