pcl_ros in CMakeLists.txt

edit

I want to work with pcl_ros in a package but I don't know how to include it in the CMakeLists.txt file. I tried to use:

find_package(catkin REQUIRED
    roscpp
    sensor_msgs
    pcl_ros
)

Unfortunately it is not working. I get an error when compiling.

I am using ROS Hydro (catkin system) but the perception package (pcl_ros) was downloaded manually and is inside my workspace.

I would appreciate if you can help me.

[EDIT]

CMake Error at /home/summitxl/catkin_ws/build/Compilados/pcl_msgs-hydro-devel/cmake/pcl_msgs-genmsg.cmake:53 (add_custom_target):
  add_custom_target cannot create target "pcl_msgs_generate_messages_cpp"
  because another target with the same name already exists.  The existing
  target is a custom target created in source directory
  "/home/summitxl/catkin_ws/src/pcl2_to_scan".  See documentation for policy
  CMP0002 for more details.
Call Stack (most recent call first):
  /home/summitxl/ros_catkin_ws/install_isolated/share/genmsg/cmake/genmsg-extras.cmake:299 (include)
  Compilados/pcl_msgs-hydro-devel/CMakeLists.txt:14 (generate_messages)    

CMake Error at /home/summitxl/catkin_ws/build/Compilados/pcl_msgs-hydro-devel/cmake/pcl_msgs-genmsg.cmake:100 (add_custom_target):
  add_custom_target cannot create target "pcl_msgs_generate_messages_lisp"
  because another target with the same name already exists.  The existing
  target is a custom target created in source directory
  "/home/summitxl/catkin_ws/src/pcl2_to_scan".  See documentation for policy
  CMP0002 for more details.
Call Stack (most recent call first):
  /home/summitxl/ros_catkin_ws/install_isolated/share/genmsg/cmake/genmsg-extras.cmake:299 (include)
  Compilados/pcl_msgs-hydro-devel/CMakeLists.txt:14 (generate_messages)


CMake Error at /home/summitxl/catkin_ws/build/Compilados/pcl_msgs-hydro-devel/cmake/pcl_msgs-genmsg.cmake:147 (add_custom_target):
  add_custom_target cannot create target "pcl_msgs_generate_messages_py"
  because another target with the same name already exists.  The existing
  target is a custom target created in source directory
  "/home/summitxl/catkin_ws/src/pcl2_to_scan".  See documentation for policy
  CMP0002 for more details.
Call Stack (most recent call first):
  /home/summitxl/ros_catkin_ws/install_isolated/share/genmsg/cmake/genmsg-extras.cmake:299 (include)
  Compilados/pcl_msgs-hydro-devel/CMakeLists.txt:14 (generate_messages)

CMake Error at /home/summitxl/ros_catkin_ws/install_isolated/share/dynamic_reconfigure/cmake/extras.cmake:60 (add_custom_target):
  add_custom_target cannot create target "pcl_ros_gencfg" because another
  target with the same name already exists.  The existing target is a custom
  target created in source directory
  "/home/summitxl/catkin_ws/src/pcl2_to_scan".  See documentation for policy
  CMP0002 for more details.
Call Stack (most recent call first):
  perception_pcl-hydro-devel/pcl_ros/CMakeLists.txt:43 (generate_dynamic_reconfigure_options)

CMake Warning at navigation-hydro-devel/costmap_2d/CMakeLists.txt:143 (find_package):
  By not providing "Findgtest.cmake" in CMAKE_MODULE_PATH this project has
  asked CMake to find a package configuration file provided by "gtest", but
  CMake did not find one.

  Could not find a package configuration file provided by "gtest" with any of
  the following names:

    gtestConfig.cmake
    gtest-config.cmake

  Add the installation prefix of "gtest" to CMAKE_PREFIX_PATH or set
  "gtest_DIR" to a directory containing one of the above files.  If "gtest"
  provides a separate development package or SDK, be sure it has been
  installed.