diff --git a/src/glsl/builtins/tools/generate_builtins.py b/src/glsl/builtins/tools/generate_builtins.py
index 8b11338e8c7..1cf12a148c6 100755
--- a/src/glsl/builtins/tools/generate_builtins.py
+++ b/src/glsl/builtins/tools/generate_builtins.py
@@ -2,6 +2,7 @@
 # -*- coding: utf-8 -*-
 
 import re
+import sys
 from glob import glob
 from os import path
 from subprocess import Popen, PIPE