CMake Gazebo warnings with ROS

edit

When I build my package in ROS, I get the following list of warnings:

cc1plus: warning: /usr/lib/x86_64-linux-gnu/libgazebo.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libgazebo_client.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libgazebo_gui.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libgazebo_sensors.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libgazebo_rendering.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libgazebo_physics.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libgazebo_ode.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libgazebo_transport.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libgazebo_msgs.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libgazebo_util.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libgazebo_common.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libgazebo_gimpact.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libgazebo_opcode.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libgazebo_opende_ou.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libgazebo_math.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libgazebo_ccd.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libboost_thread.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libboost_signals.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libboost_system.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libboost_filesystem.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libboost_program_options.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libboost_regex.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libboost_iostreams.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libboost_date_time.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libboost_chrono.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libboost_atomic.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libpthread.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libprotobuf.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libsdformat.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libignition-math2.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libOgreMain.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libOgreTerrain.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libOgrePaging.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libgazebo.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libgazebo_client.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libgazebo_gui.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libgazebo_sensors.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libgazebo_rendering.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libgazebo_physics.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libgazebo_ode.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libgazebo_transport.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libgazebo_msgs.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libgazebo_util.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libgazebo_common.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libgazebo_gimpact.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libgazebo_opcode.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libgazebo_opende_ou.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libgazebo_math.so: not a directory
cc1plus: warning: /usr/lib/x86_64-linux-gnu/libgazebo_ccd ...