From Nico Kruithof, "For the VNC server, it seems that the wrong include path is used.

Instead of 
INCLUDE_DIRECTORIES(${LIBVNCCLIENT_INCLUDE_DIR})
the CMake variable 
INCLUDE_DIRECTORIES(${LIBVNCSERVER_INCLUDE_DIR})
should be used.

Attached is a fix for src/osgPlugins/vnc/CMakeLists.txt"

src/osgPlugins/vnc/CMakeLists.txt

@@ -1,6 +1,6 @@
 SET(TARGET_SRC ReaderWriterVNC.cpp )
 
-INCLUDE_DIRECTORIES(${LIBVNCCLIENT_INCLUDE_DIR})
+INCLUDE_DIRECTORIES(${LIBVNCSERVER_INCLUDE_DIR})
 
 SET(TARGET_EXTERNAL_LIBRARIES
     ${LIBVNCCLIENT_LIBRARY}