我尝试从google正式文档构建android内核，从头开始使用官方 build.sh ，但是得到了如下错误消息：

  VDSOSYM include/generated/vdso-offsets.h
  LDS     arch/arm64/kernel/vdso32/vdso.lds
  VDSOC32   arch/arm64/kernel/vdso32/vgettimeofday.o
  VDSOA32   arch/arm64/kernel/vdso32/sigreturn.o
  HOSTCC  arch/arm64/kernel/vdso32/../../../arm/vdso/vdsomunge
clang-5.0: warning: optimization flag '-fno-delete-null-pointer-checks' is not supported [-Wignored-optimization-argument]
  VDSOL32   arch/arm64/kernel/vdso32/vdso.so.raw
/..//bin/ld: unrecognised emulation mode: armelf_linux_eabi