title: Compiling PCL 1.7 on Ubuntu 16.04 , errors in CMake generated Makefile
body: <p>I'm trying to get PCL 1.7 (The point cloud library, not the other pcl) working on Ubuntu 16.04. I eventually hope to use for C++ stuff, but right now I'm just trying to get the examples working. I'm using the default compilers that came with Ubuntu (GNU 5.3.1), and Cmake version 3.5.2. I've been following the directions on PCL's website (<a href="http://pointclouds.org/documentation/tutorials/using_pcl_pcl_config.php" rel="noreferrer">here</a> and <a href="http://pointclouds.org/documentation/tutorials/writing_pcd.php#writing-pcd" rel="noreferrer">here</a>), but am currently stuck at the point where I use the 'make' command after letting Cmake build the things it wants to build. This is the error I get</p>
  
  <pre><code>[ 50%] Building CXX object CMakeFiles/pcd_write.dir/pcd_write.cpp.o
  &lt;command-line&gt;:0:15: warning: missing whitespace after the macro name
  make[2]: *** No rule to make target '/usr/lib/x86_64-linux-gnu/libproj.so', needed by 'pcd_write'.  Stop.
  CMakeFiles/Makefile2:67: recipe for target 'CMakeFiles/pcd_write.dir/all' failed
  make[1]: *** [CMakeFiles/pcd_write.dir/all] Error 2
  Makefile:83: recipe for target 'all' failed
  make: *** [all] Error 2
  </code></pre>
  
  <p>Cmake also gives me warnings when I'm building things, and those are here. They don't stop it from running, but they might be relevant.</p>
  
  <pre><code>-- Found OpenNI2: /usr/lib/libOpenNI2.so  
  ** WARNING ** io features related to pcap will be disabled
  ** WARNING ** io features related to png will be disabled
  -- The imported target "vtkRenderingPythonTkWidgets" references the file
     "/usr/lib/x86_64-linux-gnu/libvtkRenderingPythonTkWidgets.so"
  but this file does not exist.  Possible reasons include:
  * The file was deleted, renamed, or moved to another location.
  * An install or uninstall procedure did not complete successfully.
  * The installation package was faulty and contained
     " /usr/lib/cmake/vtk-6.2/VTKTargets.cmake"
      but not all the files it references.
  </code></pre>
  
  <p>Also, in case it's relevant, I did a potentially stupid thing earlier when it was giving me similar warnings about VTK. It was telling me that /user/bin/vtk was renamed or something, and it was.  This version of VTK called itself vtk6. I tried to root around in the makefiles to find that and change it so Cmake would know to look for vtk6, but I couldn't find it anywhere, so I went into the bin and made a copy of vtk6 named vtk, and it stopped giving me a warning. </p>
  
  <p>Other relevant versions of stuff I'm using are eigen3 3.2.92, boost 1.58.0, flan 1.8.4, vtk6, and libopenni2 version 2.2.0.3</p>
  
  <p>Again, not sure how much of this is actually important, but better to be too specific than too vague IMO.</p>