Changes from Jonathan Riehl to allow his pgen extension (PEP 269) to
work.  This includes some more code that used to be part of pgen in
the main parser; I'm okay with that.  I'll see if the Windows build
needs work next.
diff --git a/Parser/pgen.c b/Parser/pgen.c
index f3fdb46..453deb4 100644
--- a/Parser/pgen.c
+++ b/Parser/pgen.c
@@ -669,6 +669,11 @@
 	return g;
 }
 
+grammar *
+Py_pgen(node *n)
+{
+  return pgen(n);
+}
 
 /*