Backported PyCapsule from 3.1, and converted most uses of
CObject to PyCapsule.
diff --git a/Include/Python.h b/Include/Python.h
index eac9f48..75d2b10 100644
--- a/Include/Python.h
+++ b/Include/Python.h
@@ -107,6 +107,7 @@
 #include "classobject.h"
 #include "fileobject.h"
 #include "cobject.h"
+#include "pycapsule.h"
 #include "traceback.h"
 #include "sliceobject.h"
 #include "cellobject.h"