diff --git a/build/.gdbinit.py.in b/build/.gdbinit.py.in
index 755007116054..ec8c11b51b11 100644
--- a/build/.gdbinit.py.in
+++ b/build/.gdbinit.py.in
@@ -1,5 +1,6 @@
 #filter substitution
 
+import os
 import sys
 
 sys.path.append(os.path.join('@topsrcdir@', 'js', 'src', 'gdb'))