Josef - 2020-04-20

Hi,
when following the installation commands, the command
cmake -G "Unix Makefiles" ..
turns the message:
Found PythonInterp: /usr/bin/python (found version "2.7.16")
CMake Error at /usr/share/cmake-3.7/Modules/FindPackageHandleStandardArgs.cmake:138 (message):
Could NOT find FLEX (missing: FLEX_EXECUTABLE)
Call Stack (most recent call first):
/usr/share/cmake-3.7/Modules/FindPackageHandleStandardArgs.cmake:378 (_FPHSA_FAILURE_MESSAGE)
/usr/share/cmake-3.7/Modules/FindFLEX.cmake:219 (FIND_PACKAGE_HANDLE_STANDARD_ARGS)
CMakeLists.txt:98 (find_package)

-- Configuring incomplete, errors occurred!
See also "/home/pi/Pan-Tilt-HAT/doxygen/build/CMakeFiles/CMakeOutput.log".

How can I solve this?

Thank You for help :)