問題如下：
$ ARCH=aarch64 CROSS_COMPILE=aarch64-linux-gnu- make O=out
Using busybox-1.37.0 as source for busybox
GEN busybox-1.37.0/out/Makefile
CC libbb/hash_md5_sha.o
busybox-1.37.0/libbb/hash_md5_sha.c: In function ‘sha1_end’:
busybox-1.37.0/libbb/hash_md5_sha.c:1316:35: error: ‘sha1_process_block64_shaNI’ undeclared (first use in this function); did you mean ‘sha1_process_block64’?
1316 | || ctx->process_block == sha1_process_block64_shaNI
| ^~~~~~~~~~~~~~~~~~~~~~~~~~
| sha1_process_block64
busybox-1.37.0/libbb/hash_md5_sha.c:1316:35: note: each undeclared identifier is reported only once for each function it appears in
解法如下：
$ ARCH=aarch64 CROSS_COMPILE=aarch64-linux-gnu- make O=out menuconfig
Settings --> [ ] SHA1: Use hardware accelerated instructions if possible
Settings --> [ ] SHA256: Use hardware accelerated instructions if possible