diff --git a/setupext.py b/setupext.py
index 1b2506da2c6b..15c59053c2b9 100644
--- a/setupext.py
+++ b/setupext.py
@@ -1341,7 +1341,7 @@ def add_flags(self, ext):
                                        default_libraries=['qhull'])
         else:
             ext.include_dirs.append('extern')
-            ext.sources.extend(glob.glob('extern/libqhull/*.c'))
+            ext.sources.extend(sorted(glob.glob('extern/libqhull/*.c')))
 
 
 class TTConv(SetupPackage):