First pass followups

[stonier]

From PR #2.

• Don't use isystem, i.e. snippet from kobuki_core/CMakeLists.txt#L8-L10
• Check it's using same ecl cxx and warnings for consistency (don't bring in ecl as a dependency though)
• On foxy, with rosdep: No definition of [ros_testing] for OS version [focal]

[clalancette]

* On foxy, with `rosdep`: `No definition of [ros_testing] for OS version [focal]`

FYI, I think your rosdep database may have been out-of-date. At least, that package should exist on Foxy/Focal:

$ sudo apt-cache policy ros-foxy-ros-testing
ros-foxy-ros-testing:
  Installed: 0.2.1-1focal.20200827.222316
  Candidate: 0.2.1-1focal.20200827.222316
  Version table:
 *** 0.2.1-1focal.20200827.222316 500
        500 http://packages.ros.org/ros2-testing/ubuntu focal/main amd64 Packages
        100 /var/lib/dpkg/status

[brianlmerritt]

Once this and other repositories are setup in _ws/src, running rosdep install --from-paths src --ignore-src -r -y should cover the installs. If not, then sudo apt install -y ros-foxy-ros-testing ros-foxy-ecl-config ros-foxy-ecl-tools