[CMake][Fix Bug] Correct the integration of optional dependency ocotomap

src/CMakeLists.txt

@@ -102,7 +102,9 @@ add_library(${LIBRARY_NAME}
   )
 TARGET_LINK_LIBRARIES(${LIBRARY_NAME} ${Boost_LIBRARIES})
 PKG_CONFIG_USE_DEPENDENCY(${LIBRARY_NAME} ccd)
-PKG_CONFIG_USE_DEPENDENCY(${LIBRARY_NAME} octomap)
+IF(OCTOMAP_FOUND)
+  PKG_CONFIG_USE_DEPENDENCY(${LIBRARY_NAME} octomap)
+ENDIF(OCTOMAP_FOUND)
 #PKG_CONFIG_USE_DEPENDENCY(${LIBRARY_NAME} flann)