diff --git a/setup.py b/setup.py
index ffc7eb368..446af345f 100644
--- a/setup.py
+++ b/setup.py
@@ -63,6 +63,7 @@ cython_sources = [
     chunker_source,
     hashindex_source,
     item_source,
+    crc32_source,
 
     platform_posix_source,
     platform_linux_source,