我想创建LwIP库文件，为此，当我在编译代码时遇到此类错误。在这些环境中我较新，请帮助我解决错误。
tcpip.c:(.text+0x4e1): undefined reference to `sys_mbox_trypost'
/tmp/ccICMW06.o: In function `tcpip_send_msg_wait_sem':
tcpip.c:(.text+0x522): undefined reference to `sys_mutex_lock'
tcpip.c:(.text+0x539): undefined reference to `sys_mutex_unlock'
/tmp/ccICMW06.o: In function `tcpip_api_call':
tcpip.c:(.text+0x55a): undefined reference to `sys_mutex_lock'
tcpip.c:(.text+0x574): undefined reference to `sys_mutex_unlock'
/tmp/ccICMW06.o: In function `tcpip_callbackmsg_trycallback':
sys.c:(.text+0x2d): undefined reference to `sys_sem_new'
sys.c:(.text+0x47): undefined reference to `sys_arch_sem_wait'
sys.c:(.text+0x53): undefined reference to `sys_sem_free'
/tmp/cc6o04mE.o: In function `lwip_tcp_conn_report':
lwiperf.c:(.text+0x15a): undefined reference to `sys_now'
/tmp/cc6o04mE.o: In function `lwiperf_tcp_client_send_more':
lwiperf.c:(.text+0x3a3): undefined reference to `sys_now'
/tmp/cc6o04mE.o: In function `lwiperf_tcp_client_connected':
lwiperf.c:(.text+0x688): undefined reference to `sys_now'
/tmp/cc6o04mE.o: In function `lwiperf_tx_start_impl':
lwiperf.c:(.text+0x80c): undefined reference to `sys_now'