diff --git a/tools/VERSION b/tools/VERSION
index 0e38057..3572a33 100644
--- a/tools/VERSION
+++ b/tools/VERSION
@@ -28,4 +28,4 @@
 MINOR 12
 PATCH 0
 PRERELEASE 2
-PRERELEASE_PATCH 1
+PRERELEASE_PATCH 2
diff --git a/tools/clean_output_directory.py b/tools/clean_output_directory.py
index 79df929..f0f0426 100755
--- a/tools/clean_output_directory.py
+++ b/tools/clean_output_directory.py
@@ -5,6 +5,7 @@
 # BSD-style license that can be found in the LICENSE file.
 #
 
+import os
 import shutil
 import sys
 import subprocess