build.sh: add ability to genrate tags for IDEs

Change-Id: I971e5fe983aa745cf64697ee2c4ad0ff63a3c5dc
Signed-off-by: Thierry Strudel <tstrudel@google.com>
diff --git a/build.sh b/build.sh
index 4da6dfc..761b6c8 100755
--- a/build.sh
+++ b/build.sh
@@ -223,6 +223,15 @@
 fi
 fi
 
+if [ "${TAGS_CONFIG}" != "" ]; then
+  echo "========================================================"
+  echo " Running tags command:"
+  set -x
+  (cd ${KERNEL_DIR} && SRCARCH=${ARCH} ./scripts/tags.sh ${TAGS_CONFIG})
+  set +x
+  exit 0
+fi
+
 echo "========================================================"
 echo " Building kernel"