Delete generated/README.txt (the contents are in code.html now) so clean can just remove the "generated" directory entirely.
diff --git a/scripts/make.sh b/scripts/make.sh
index 165b8f1..dab5206 100755
--- a/scripts/make.sh
+++ b/scripts/make.sh
@@ -21,6 +21,7 @@
   "$@"
 }
 
+mkdir -p generated
 echo "Make generated/config.h from $KCONFIG_CONFIG."
 
 # This long and roundabout sed invocation is to make old versions of sed happy.