address gcc6 build error

With gcc6, compiling fails with `stdlib.h: No such file or directory`,
as including '-isystem /usr/include' breaks with gcc6, cf.,
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70129.

This commit addresses this issue for this package in the same way
it was addressed in various other ROS packages. A list of related
commits and pull requests is at:

  ros/rosdistro#12783

The SYSTEM attribute for the eigen and pcl include directories
was added in commit 9e876d2 [1] on 2012-09-16 during the
package's transition to ROS Groovy. The reason for using
the SYSTEM attribute cannot be inferred from that commit.

This attribute remained in the CMakeLists.txt during further
refinements in commits be4aebd [2] and 3a15614 [3]
on 2014-02-24, and commit 4a7578b [4] on 2016-10-23.

[1] ros-planning@9e876d2
[2] ros-planning@be4aebd
[3] ros-planning@3a15614
[4] ros-planning@4a7578b

Signed-off-by: Lukas Bulwahn <[email protected]>

move_slow_and_clear/CMakeLists.txt

@@ -20,9 +20,8 @@ find_package(Boost REQUIRED COMPONENTS thread)
 include_directories(
     include
     ${catkin_INCLUDE_DIRS}
-    SYSTEM
-        ${EIGEN3_INCLUDE_DIRS}
-        ${PCL_INCLUDE_DIRS}
+    ${EIGEN3_INCLUDE_DIRS}
+    ${PCL_INCLUDE_DIRS}
 )
 add_definitions(${EIGEN3_DEFINITIONS})
 

navfn/CMakeLists.txt

@@ -22,7 +22,6 @@ remove_definitions(-DDISABLE_LIBUSB-1.0)
 include_directories(
     include
     ${catkin_INCLUDE_DIRS}
-    SYSTEM
     ${EIGEN3_INCLUDE_DIRS}
     ${PCL_INCLUDE_DIRS}
 )