Undefined symbols for architecture arm64:
  "_event_add", referenced from:
      _my_event_add in lto.o
      _my_timer_add in lto.o
      _my_signal_add in lto.o
  "_event_base_dispatch", referenced from:
      _my_event_base_dispatch in lto.o
  "_event_base_free", referenced from:
      _my_event_base_free in lto.o
  "_event_base_get_method", referenced from:
      _ub_resolve in lto.o
  "_event_base_loopexit", referenced from:
      _my_event_base_loopexit in lto.o
  "_event_base_new", referenced from:
      _ub_resolve in lto.o
  "_event_base_set", referenced from:
      _my_event_new in lto.o
      _my_signal_new in lto.o
      _my_timer_add in lto.o
  "_event_del", referenced from:
      _my_event_del in lto.o
      _my_timer_del in lto.o
      _my_signal_del in lto.o
  "_event_get_version", referenced from:
      _ub_resolve in lto.o
  "_event_set", referenced from:
      _my_event_new in lto.o
      _my_signal_new in lto.o
      _my_timer_add in lto.o
  "_nghttp2_session_callbacks_del", referenced from:
      _comm_point_delete in lto.o
  "_nghttp2_session_del", referenced from:
      _comm_point_close in lto.o
  "_nghttp2_session_get_stream_user_data", referenced from:
      _http2_submit_response_read_callback in lto.o
  "_nghttp2_session_recv", referenced from:
      _comm_point_http_handle_callback in lto.o
  "_nghttp2_session_send", referenced from:
      _comm_point_http_handle_callback in lto.o
  "_nghttp2_session_want_read", referenced from:
      _comm_point_http_handle_callback in lto.o
      _comm_point_http_handle_callback in lto.o
  "_nghttp2_session_want_write", referenced from:
      _comm_point_http_handle_callback in lto.o
      _comm_point_http_handle_callback in lto.o
  "_nghttp2_strerror", referenced from:
      _mesh_send_reply in lto.o
      _mesh_send_reply in lto.o
      _comm_point_http_handle_callback in lto.o
      _comm_point_http_handle_callback in lto.o
  "_nghttp2_submit_response", referenced from:
      _mesh_send_reply in lto.o
  "_nghttp2_submit_rst_stream", referenced from:
      _mesh_send_reply in lto.o
ld: symbol(s) not found for architecture arm64
clang++: error: linker command failed with exit code 1 (use -v to see invocation)