[pygobject/pygobject-3-30] Don't use PyTypeObject.tp_print with Python 3

[Christoph Reiter <creiter src gnome org>]

commit bbe2e94bb66b5e263655083dd6ed6bb878e21b74
Author: Christoph Reiter <reiter christoph gmail com>
Date:   Fri Jun 7 16:31:23 2019 +0200

    Don't use PyTypeObject.tp_print with Python 3
    
    It was only used with Python 2 and unused/reserved with Python 3.
    Python 3.8 has renamed the slot and is now using it for something different
    which breaks our build.

 gi/pygobject-object.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
---
diff --git a/gi/pygobject-object.c b/gi/pygobject-object.c
index dbf46e1e..39c03ca3 100644
--- a/gi/pygobject-object.c
+++ b/gi/pygobject-object.c
@@ -878,7 +878,10 @@ pygobject_inherit_slots(PyTypeObject *type, PyObject *bases, gboolean check_for_
                                   offsetof(PyTypeObject, tp_iter),
                                   offsetof(PyTypeObject, tp_repr),
                                   offsetof(PyTypeObject, tp_str),
-                                  offsetof(PyTypeObject, tp_print) };
+#if PY_VERSION_HEX < 0x03000000
+                                  offsetof(PyTypeObject, tp_print),
+#endif
+    };
     gsize i;
 
     /* Happens when registering gobject.GObject itself, at least. */