Put descr name in "bad memberdescr type" error message.
diff --git a/Python/structmember.c b/Python/structmember.c
index 077be70..aa0ea9f 100644
--- a/Python/structmember.c
+++ b/Python/structmember.c
@@ -261,7 +261,8 @@
 		}
 		break;
 	default:
-		PyErr_SetString(PyExc_SystemError, "bad memberdescr type");
+		PyErr_Format(PyExc_SystemError,
+			     "bad memberdescr type for %s", l->name);
 		return -1;
 	}
 	return 0;