使用MDK-ARM μVision V5.38版本编译报如下错误：
.\build\rtthread-stm32.axf: Error: L6218E: Undefined symbol __bss_end (referred from board.o)..\build\rtthread-stm32.axf: Error: L6218E: Undefined symbol __fsymtab_start (referred from shell.o)..\build\rtthread-stm32.axf: Error: L6218E: Undefined symbol __fsymtab_end (referred from shell.o)..\build\rtthread-stm32.axf: Error: L6218E: Undefined symbol __vsymtab_start (referred from shell.o)..\build\rtthread-stm32.axf: Error: L6218E: Undefined symbol __vsymtab_end (referred from shell.o).
请问如何解决？
