To avoid build break:
ld: riscv-none-elf/lib/rv64imafdc_zicsr/lp64d/crt0.o: in function `.L0 ':
(.text+0x8): undefined reference to `__bss_start'
ld: (.text+0x10): undefined reference to `_end'
ld: (.text+0x36): undefined reference to `main'
collect2: error: ld returned 1 exit status
Signed-off-by: chao an <anchao@lixiang.com>
02acf2d2a4