Make header install obey MSGPACK_ENABLE_CXX

Author: lluixhi

CMakeLists.txt

@@ -258,7 +258,10 @@ ENDIF ()
 INSTALL (TARGETS ${MSGPACK_INSTALLTARGETS} RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}
                                            LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
                                            ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR})
-INSTALL (DIRECTORY include DESTINATION ${CMAKE_INSTALL_PREFIX})
+FOREACH (file ${msgpackc_HEADERS})
+    GET_FILENAME_COMPONENT (dir ${file} DIRECTORY)
+    INSTALL (FILES ${file} DESTINATION ${CMAKE_INSTALL_PREFIX}/${dir})
+ENDFOREACH ()
 IF (NOT MSVC)
     INSTALL (FILES ${CMAKE_CURRENT_BINARY_DIR}/msgpack.pc DESTINATION ${CMAKE_INSTALL_LIBDIR}/pkgconfig)
 ENDIF ()