diff --git a/chapter08/flex.xml b/chapter08/flex.xml
index d05474f03..d2c08d0eb 100644
--- a/chapter08/flex.xml
+++ b/chapter08/flex.xml
@@ -51,6 +51,10 @@
This is not present, so we use an environment variable to skip this process.
Now, prepare Flex for compilation: -->
+ &update-config-text;
+
+tar -C build-aux &update-config-arg;
+
Prepare Flex for compilation:
./configure --prefix=/usr \