build_library: Add developer mode flags to MiniOS in developer image

BUG=b:206814209
TEST=./build_image --board=${BOARD} base test

Cq-Depend: chromium:3469722
Change-Id: I67514a15b5202dad6905cec454ee3538122af673
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosutils/+/3361248
Reviewed-by: Jae Hoon Kim <kimjae@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Tested-by: Henry Barnor <hbarnor@chromium.org>
Reviewed-by: Alex Klein <saklein@chromium.org>
Commit-Queue: Henry Barnor <hbarnor@chromium.org>
1 file changed