Build with ROS option

[Hanzhe Teng]

The following is what I have done:

git clone https://github.com/jedeschaud/ct_icp.git
cd ct_icp
mkdir .cmake-build-superbuild && cd .cmake-build-superbuild
cmake ../superbuild -DWITH_ROS=ON

Then the prompt is

-- The C compiler identification is GNU 9.4.0
-- The CXX compiler identification is GNU 9.4.0
-- Check for working C compiler: /usr/bin/cc
-- Check for working C compiler: /usr/bin/cc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Detecting C compile features
-- Detecting C compile features - done
-- Check for working CXX compiler: /usr/bin/c++
-- Check for working CXX compiler: /usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Configuring done
-- Generating done
CMake Warning:
  Manually-specified variables were not used by the project:

    WITH_ROS


-- Build files have been written to: /home/hteng/ct_icp/.cmake-build-superbuild

I have checked the source files and neither the main CMakeLists nor the superbuild CMakeLists has such a flag.

Can you please update the instructions on how to build with ROS wrapper?