cmake: use CMake standard convention for Assimp

CMakeLists.txt

@@ -116,7 +116,7 @@ if(HPP_FCL_HAS_QHULL)
     )
 endif()
 
-ADD_REQUIRED_DEPENDENCY("assimp >= 2.0")
+ADD_PROJECT_DEPENDENCY(assimp REQUIRED PKG_CONFIG_REQUIRES "assimp >= 2.0.0")
 
 SET(${PROJECT_NAME}_HEADERS
   include/hpp/fcl/collision_data.h

src/CMakeLists.txt

@@ -161,6 +161,7 @@ TARGET_LINK_LIBRARIES(${LIBRARY_NAME}
   ${Boost_THREAD_LIBRARY}
   ${Boost_DATE_TIME_LIBRARY}
   ${Boost_SYSTEM_LIBRARY}
+  ${assimp_LIBRARY}
 #  Boost::thread
 #  Boost::date_time
 #  Boost::system
@@ -176,6 +177,7 @@ endif()
 target_include_directories(${LIBRARY_NAME}
   SYSTEM PUBLIC
   ${EIGEN3_INCLUDE_DIR}
+  ${assimp_INCLUDE_DIR}
   ${Boost_INCLUDE_DIRS}
   )
 
@@ -184,8 +186,7 @@ target_include_directories(${LIBRARY_NAME}
   $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>
   )
 
-PKG_CONFIG_USE_DEPENDENCY(${LIBRARY_NAME} assimp)
-if (NOT ${ASSIMP_VERSION} VERSION_LESS "2.0.1150")
+if (NOT ${assimp_VERSION} VERSION_LESS "2.0.1150")
   target_compile_definitions(${LIBRARY_NAME} PRIVATE -DHPP_FCL_USE_ASSIMP_UNIFIED_HEADER_NAMES)
   message(STATUS "Assimp version has unified headers")
 else()