Use Py_ssize_t for counts and sizes.
Convert Py_ssize_t using PyInt_FromSsize_t
diff --git a/Objects/structseq.c b/Objects/structseq.c
index 023a1fd..b266d6a 100644
--- a/Objects/structseq.c
+++ b/Objects/structseq.c
@@ -247,7 +247,7 @@
 	PyObject* tup;
 	PyObject* dict;
 	PyObject* result;
-	long n_fields, n_visible_fields, n_unnamed_fields;
+	Py_ssize_t n_fields, n_visible_fields, n_unnamed_fields;
 	int i;
 	
 	n_fields = REAL_SIZE(self);