我有两个构建目录的cmake文件，然后尝试编译使用该库的示例。存储在项目根${CMAKE_SOURCE_DIR}中的第一个CMakeLists.txt文件的内容为：
cmake_minimum_required(VERSION 2.8 FATAL_ERROR)
project("lsd_point_pair")
SET(EXECUTABLE_OUTPUT_PATH ${PROJECT_BINARY_DIR}/bin)
SET(LIBRARY_OUTPUT_PATH ${PROJECT_BINARY_DIR}/lib)
#Note: Eclipse automatically picks up include paths with this on!
SET(CMAKE_VERBOSE_MAKEFILE ON)
SET(CMAKE_CXX_FLAGS "-g")
find_package(PCL 1.7 REQUIRED)
include_directories(${PCL_INCLUDE_DIRS})
link_directories(${PCL_LIBRARY_DIRS})
add_definitions(${PCL_DEFINITIONS})
set(BOOST_LIBS program_options)
find_package(Boost COMPONENTS ${BOOST_LIBS} REQUIRED)
include_directories(${Boost_INCLUDE_DIRS})
link_directories(${Boost_LIBRARY_DIRS})
MESSAGE(" Boost_LIBRARIES: ${Boost_LIBRARIES}")
include_directories(${PROJECT_BINARY_DIR})
link_directories(${PROJECT_BINARY_DIR}/lib})
add_library(lsd_obj_rec_ransac lsd_obj_rec_ransac.cpp lsd_obj_rec_ransac.h lsd_point_pair_model_library.cpp lsd_point_pair_model_library.h ndim_voxel_structure.h orr_octree_cloud.h orr_octree_cloud.cpp)
target_link_libraries(lsd_obj_rec_ransac ${PCL_LIBRARIES} ${Boost_LIBRARIES})
######## subdirectories #########
add_subdirectory(examples)
在${CMAKE_SOURCE_DIR} /示例中，我有以下CMakeLists.txt文件：
add_executable(example_pcl_lsd_point_pair example_pcl_lsd_point_pair.cpp)
target_link_libraries(example_pcl_lsd_point_pair lsd_obj_rec_ransac ${Boost_LIBRARIES} ${PCL_LIBRARIES})
成功运行cmake后，我运行make并得到链接错误：
CMakeFiles/example_pcl_lsd_point_pair.dir/example_pcl_lsd_point_pair.cpp.o: In function `~LSDObjRecRANSAC':
make[2]: Leaving directory `/media/Data/Documents/Grad/research/Projects/LSDPointPairs/qtcreator-build'
make[1]: Leaving directory `/media/Data/Documents/Grad/research/Projects/LSDPointPairs/qtcreator-build'
/home/mustafa/projects/LSDPointPairs/examples/../lsd_obj_rec_ransac.h:44: undefined reference to `pcl::recognition::ORROctreeCloud::~ORROctreeCloud()'
/home/mustafa/projects/LSDPointPairs/examples/../lsd_obj_rec_ransac.h:44: undefined reference to `pcl::recognition::ORROctreeCloud::~ORROctreeCloud()'
../lib/liblsd_obj_rec_ransac.a(lsd_obj_rec_ransac.cpp.o): In function `LSDObjRecRANSAC':
/home/mustafa/projects/LSDPointPairs/lsd_obj_rec_ransac.cpp:18: undefined reference to `pcl::recognition::LSDPointPairModelLibrary::LSDPointPairModelLibrary(float, float, float)'
/home/mustafa/projects/LSDPointPairs/lsd_obj_rec_ransac.cpp:18: undefined reference to `pcl::recognition::ORROctreeCloud::ORROctreeCloud()'
/home/mustafa/projects/LSDPointPairs/lsd_obj_rec_ransac.cpp:18: undefined reference to `pcl::recognition::ORROctreeCloud::~ORROctreeCloud()'
../lib/liblsd_obj_rec_ransac.a(lsd_point_pair_model_library.cpp.o): In function `LSDPointPairModel':
/home/mustafa/projects/LSDPointPairs/lsd_point_pair_model_library.h:36: undefined reference to `pcl::recognition::ORROctreeCloud::ORROctreeCloud()'
/home/mustafa/projects/LSDPointPairs/lsd_point_pair_model_library.h:36: undefined reference to `pcl::recognition::ORROctreeCloud::~ORROctreeCloud()'
../lib/liblsd_obj_rec_ransac.a(lsd_point_pair_model_library.cpp.o): In function `~LSDPointPairModel':
/home/mustafa/projects/LSDPointPairs/lsd_point_pair_model_library.h:27: undefined reference to `pcl::recognition::ORROctreeCloud::~ORROctreeCloud()'
/home/mustafa/projects/LSDPointPairs/lsd_point_pair_model_library.h:27: undefined reference to `pcl::recognition::ORROctreeCloud::~ORROctreeCloud()'
collect2: ld returned 1 exit status
make[2]: *** [bin/example_pcl_lsd_point_pair] Error 1
make[1]: *** [examples/CMakeFiles/example_pcl_lsd_point_pair.dir/all] Error 2
make: *** [all] Error 2
库已成功构建，因为我看到生成了liblsd_obj_rec_ransac.a文件。但是在尝试编译示例时会出现问题。我做错了什么？