diff --git a/setup.py b/setup.py
index <HASH>..<HASH> 100644
--- a/setup.py
+++ b/setup.py
@@ -7,6 +7,7 @@ try:
 except ImportError:
     on_rtd = True
     numpy = None
+    build_ext = None
     
 import os
trying to make rtd-working