d:/zhtong/risc_v/tool/hbird-opensource/hbird-eclipse_2018_09/gnu mcu eclipse/risc-v embedded gcc/7.2.0-4-20180606-1631/bin/../lib/gcc/riscv-none-embed/7.2.0/../../../../riscv-none-embed/lib/rv32imac/ilp32libg.a(lib_a-exit.o): In function `.L0 ':

exit.c:(.text.exit+0x1e): undefined reference to `_exit'

d:/zhtong/risc_v/tool/hbird-opensource/hbird-eclipse_2018_09/gnu mcu eclipse/risc-v embedded gcc/7.2.0-4-20180606-1631/bin/../lib/gcc/riscv-none-embed/7.2.0/../../../../riscv-none-embed/lib/rv32imac/ilp32libg.a(lib_a-sbrkr.o): In function `.L0 ':

sbrkr.c:(.text._sbrk_r+0xe): undefined reference to `_sbrk'

d:/zhtong/risc_v/tool/hbird-opensource/hbird-eclipse_2018_09/gnu mcu eclipse/risc-v embedded gcc/7.2.0-4-20180606-1631/bin/../lib/gcc/riscv-none-embed/7.2.0/../../../../riscv-none-embed/lib/rv32imac/ilp32libg.a(lib_a-writer.o): In function `.L0 ':

writer.c:(.text._write_r+0x14): undefined reference to `_write'

d:/zhtong/risc_v/tool/hbird-opensource/hbird-eclipse_2018_09/gnu mcu eclipse/risc-v embedded gcc/7.2.0-4-20180606-1631/bin/../lib/gcc/riscv-none-embed/7.2.0/../../../../riscv-none-embed/lib/rv32imac/ilp32libg.a(lib_a-closer.o): In function `.L0 ':

closer.c:(.text._close_r+0xe): undefined reference to `_close'

d:/zhtong/risc_v/tool/hbird-opensource/hbird-eclipse_2018_09/gnu mcu eclipse/risc-v embedded gcc/7.2.0-4-20180606-1631/bin/../lib/gcc/riscv-none-embed/7.2.0/../../../../riscv-none-embed/lib/rv32imac/ilp32libg.a(lib_a-lseekr.o): In function `.L0 ':

lseekr.c:(.text._lseek_r+0x14): undefined reference to `_lseek'

d:/zhtong/risc_v/tool/hbird-opensource/hbird-eclipse_2018_09/gnu mcu eclipse/risc-v embedded gcc/7.2.0-4-20180606-1631/bin/../lib/gcc/riscv-none-embed/7.2.0/../../../../riscv-none-embed/lib/rv32imac/ilp32libg.a(lib_a-readr.o): In function `.L0 ':

readr.c:(.text._read_r+0x14): undefined reference to `_read'

d:/zhtong/risc_v/tool/hbird-opensource/hbird-eclipse_2018_09/gnu mcu eclipse/risc-v embedded gcc/7.2.0-4-20180606-1631/bin/../lib/gcc/riscv-none-embed/7.2.0/../../../../riscv-none-embed/lib/rv32imac/ilp32libg.a(lib_a-fstatr.o): In function `.L0 ':

fstatr.c:(.text._fstat_r+0x12): undefined reference to `_fstat'

d:/zhtong/risc_v/tool/hbird-opensource/hbird-eclipse_2018_09/gnu mcu eclipse/risc-v embedded gcc/7.2.0-4-20180606-1631/bin/../lib/gcc/riscv-none-embed/7.2.0/../../../../riscv-none-embed/lib/rv32imac/ilp32libg.a(lib_a-isattyr.o): In function `.L0 ':

isattyr.c:(.text._isatty_r+0xe): undefined reference to `_isatty'

collect2.exe: error: ld returned 1 exit status

make: *** [makefile:44: hello.elf] Error 1