Cythonize fix.

diff --git a/Cython/Build/Dependencies.py b/Cython/Build/Dependencies.py
index 7af60c1107a6a89edcd32d41a8f6e3d353c48d03..d74908f0a835480dec2f5c14c6e2cc8ccf1256f8 100644 (file)
--- a/Cython/Build/Dependencies.py
+++ b/Cython/Build/Dependencies.py
@@ -315,7 +315,7 @@ class DependencyTree(object):
     
     def immediate_dependencies(self, filename):
         all = list(self.cimported_files(filename))
-        for extern in self.cimports_and_externs(filename):
+        for extern in sum(self.cimports_and_externs(filename), ()):
             all.append(os.path.normpath(os.path.join(os.path.dirname(filename), extern)))
         return tuple(all)