diff --git a/lib/spack/spack/package.py b/lib/spack/spack/package.py
index 69b263db0c0..999b5e125ee 100644
--- a/lib/spack/spack/package.py
+++ b/lib/spack/spack/package.py
@@ -34,6 +34,7 @@
 README.
 """
 import os
+import errno
 import re
 import time
 import itertools