Index: pyyaml/trunk/ext/_yaml.h
===================================================================
--- pyyaml/trunk/ext/_yaml.h	(revision 205)
+++ pyyaml/trunk/ext/_yaml.h	(revision 331)
@@ -2,2 +2,10 @@
 #include <yaml.h>
 
+#if PY_MAJOR_VERSION >= 3
+
+#define PyString_CheckExact PyBytes_CheckExact
+#define PyString_AS_STRING  PyBytes_AS_STRING
+#define PyString_GET_SIZE   PyBytes_GET_SIZE
+#define PyString_FromStringAndSize  PyBytes_FromStringAndSize
+
+#endif