PyModule_AddObject(): Added missing exceptions.

Closes SF bug #523473.

Python/modsupport.c

@@ -488,15 +488,22 @@ int
 PyModule_AddObject(PyObject *m, char *name, PyObject *o)
 {
 	PyObject *dict;
-        if (!PyModule_Check(m) || o == NULL)
-                return -1;
+	if (!PyModule_Check(m) || o == NULL) {
+		PyErr_SetString(PyExc_TypeError,
+			    "PyModule_AddObject() needs module as first arg");
+		return -1;
+	}
 	dict = PyModule_GetDict(m);
-	if (dict == NULL)
+	if (dict == NULL) {
+		/* Internal error -- modules must have a dict! */
+		PyErr_Format(PyExc_SystemError, "module '%s' has no __dict__",
+			     PyModule_GetName(m));
+		return -1;
+	}
+	if (PyDict_SetItemString(dict, name, o))
 		return -1;
-        if (PyDict_SetItemString(dict, name, o))
-                return -1;
-        Py_DECREF(o);
-        return 0;
+	Py_DECREF(o);
+	return 0;
 }
 
 int