Fix build with Boost 1.89.0

cpp/CMakeLists.txt

@@ -145,7 +145,7 @@ if (USE_BOOST)
   if (WIN32)
     set (Boost_USE_STATIC_LIBS ON)
   endif ()
-  find_package (Boost 1.40.0 COMPONENTS date_time system thread)
+  find_package (Boost 1.40.0 COMPONENTS date_time thread OPTIONAL_COMPONENTS system)
   if (NOT Boost_FOUND)
     print_error ("Boost Date_Time/System/Thread" "Boost")
   endif ()