Flash_build: Linux binary checked in

[robertlipe]

There appears to be a Linux binary that's checked in and used during the build. This makes Macs unhappy. Should there be an OS-specific flash_build that is $PATHed or should it be using flash_build.by or something?

roberts-iMac7 customer_app % file ../../bl_iot_sdk/image_conf/flash_build
../../bl_iot_sdk/image_conf/flash_build: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, for GNU/Linux 2.6.32, BuildID[sha1]=4485007e1df54173663f148d5840c963a7e868ee, stripped