build_image: Add custom suffix to output directory

Use --output_suffix flag to add custom suffix to output directory.

BUG=none
TEST= ./build_image --output_suffix="some_string" ... and check if output dir
is generated properly. Also check w/o --output_suffix if default works fine.

Change-Id: I8f88aab3cdebe4d013a8c5d3c889b25212ed907b
Signed-off-by: Waldemar Rymarkiewicz <ext.waldemar.rymarkiewicz@tieto.com>
Reviewed-on: https://chromium-review.googlesource.com/383151
Commit-Ready: Waldemar Rymarkiewicz <waldemar.rymarkiewicz@gmail.com>
Tested-by: Waldemar Rymarkiewicz <waldemar.rymarkiewicz@gmail.com>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
diff --git a/build_image b/build_image
index 0c495dc..f73ebec 100755
--- a/build_image
+++ b/build_image
@@ -81,6 +81,8 @@
   "Toolset that this script is being used with."
 DEFINE_string version "" \
   "Overrides version number in name to this version."
+DEFINE_string output_suffix "" \
+  "Add custom suffix to output directory."
 DEFINE_boolean eclean ${FLAGS_TRUE} \
   "Do NOT call eclean before building the image (default is to call eclean)."
 
diff --git a/build_library/build_image_util.sh b/build_library/build_image_util.sh
index dc207c6..df21d11 100755
--- a/build_library/build_image_util.sh
+++ b/build_library/build_image_util.sh
@@ -18,6 +18,11 @@
 else
   IMAGE_SUBDIR="${IMAGE_SUBDIR}-${FLAGS_version}"
 fi
+
+if [ -n "${FLAGS_output_suffix}" ];  then
+  IMAGE_SUBDIR="${IMAGE_SUBDIR}-${FLAGS_output_suffix}"
+fi
+
 BUILD_DIR="${FLAGS_build_root}/${BOARD}/${IMAGE_SUBDIR}"
 OUTPUT_DIR="${FLAGS_output_root}/${BOARD}/${IMAGE_SUBDIR}"
 OUTSIDE_OUTPUT_DIR="../build/images/${BOARD}/${IMAGE_SUBDIR}"