Debian Build Failure on Dragonboard410C

Dear,
I am following the instruction from the link below to build debian on dragonboard410c.
https://github.com/Linaro/documentation/blob/master/Reference-Platform/ConsumerEdition/DragonBoard-410c/BFSDebianRPB-16.03.md

After configuration, I get the following error message.
hham@hham:~/Projects/dragonboard410c/linux$ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu-
scripts/kconfig/conf --silentoldconfig Kconfig
CHK include/config/kernel.release
CHK include/generated/uapi/linux/version.h
CHK include/generated/utsrelease.h
CHK include/generated/bounds.h
CHK include/generated/timeconst.h
CHK include/generated/asm-offsets.h
CALL scripts/checksyscalls.sh
HOSTCC scripts/extract-cert
scripts/extract-cert.c:21:25: fatal error: openssl/bio.h: No such file or directory
#include <openssl/bio.h>

I am using gcc-linaro-4.9-2014.11-x86_64_aarch64-linux-gnu.

Please, help me.

just install the missing library in your development environment
$ sudo apt-get install libssl-dev

Thank you. It works fine now.