[CMake] get boost::python only if build python interface

CMakeLists.txt

@@ -30,6 +30,8 @@ INCLUDE(cmake/boost.cmake)
 COMPUTE_PROJECT_ARGS(PROJECT_ARGS LANGUAGES CXX)
 PROJECT(${PROJECT_NAME} ${PROJECT_ARGS})
 
+SET(BOOST_COMPONENTS filesystem system thread program_options unit_test_framework)
+
 IF(BUILD_PYTHON_INTERFACE)
   FINDPYTHON()
   STRING(REGEX REPLACE "-" "_" PY_NAME ${PROJECT_NAME})
@@ -38,10 +40,9 @@ IF(BUILD_PYTHON_INTERFACE)
   SET(PYTHON_INSTALL_DIR
     ${CMAKE_INSTALL_PREFIX}/${PYTHON_SITELIB}/dynamic_graph/sot/core)
   ADD_PROJECT_DEPENDENCY(dynamic-graph-python 3.0.0 REQUIRED PKG_CONFIG_REQUIRES "dynamic-graph-python >= 3.0.0")
+  SET(BOOST_COMPONENTS ${BOOST_COMPONENTS} python)
 ENDIF(BUILD_PYTHON_INTERFACE)
 
-SET(BOOST_COMPONENTS
-  python filesystem system thread program_options unit_test_framework)
 SEARCH_FOR_BOOST()
 ADD_PROJECT_DEPENDENCY(Eigen3 REQUIRED PKG_CONFIG_REQUIRES eigen3)