Add new parser error code, E_OVERFLOW.  This error is returned when
the number of children of a node exceeds the max possible value for
the short that is used to count them.  The Python runtime converts
this parser error into the SyntaxError "expression too long."
diff --git a/Python/pythonrun.c b/Python/pythonrun.c
index 7760714..3a60e47 100644
--- a/Python/pythonrun.c
+++ b/Python/pythonrun.c
@@ -1033,6 +1033,9 @@
 	case E_INDENT:
 		msg = "inconsistent use of tabs and spaces in indentation";
 		break;
+	case E_OVERFLOW:
+		msg = "expression too long";
+		break;
 	default:
 		fprintf(stderr, "error=%d\n", err->error);
 		msg = "unknown parsing error";