CMake Error at /opt/ros/melodic/share/catkin/cmake/platform/lsb.cmake:8 (string): string no output variable specified

This error message indicates that there is an issue with the CMake configuration in your ROS Melodic installation. Specifically, it seems to be related to the "lsb.cmake" file, which is used to configure the build environment for Linux Standard Base (LSB) compliant systems. To resolve this issue, you can try the following steps: 1. Check that your ROS Melodic installation is up-to-date and properly configured. You can do this by running the following commands: ``` sudo apt-get update sudo apt-get upgrade source /opt/ros/melodic/setup.bash ``` 2. Make sure that all required dependencies are installed. You can check the list of dependencies for your package by looking at its "package.xml" file. 3. Try deleting the "build" and "devel" directories in your catkin workspace and rebuilding your package: ``` cd ~/catkin_ws rm -rf build devel catkin_make ``` 4. If none of these steps work, you may need to reinstall ROS Melodic or consult the ROS community forums for further assistance.