explicitly link c++ filesystem lib (required for some older compilers)

Author: NikolasK-source

libs/CMakeLists.txt

@@ -7,6 +7,7 @@ target_link_libraries(${Target} PRIVATE modbus)
 # ---------------------------------------- link libraries --------------------------------------------------------------
 # ======================================================================================================================
 target_link_libraries(${Target} PRIVATE rt)
+target_link_libraries(${Target} PRIVATE stdc++fs)
 
 add_subdirectory(cxxopts EXCLUDE_FROM_ALL)
 target_link_libraries(${Target} PRIVATE cxxopts)