diff --git a/configure.in b/configure.in
index 75161b0a3..405ae3f09 100644
--- a/configure.in
+++ b/configure.in
@@ -2,6 +2,7 @@ dnl Process this file with autoconf to produce a configure script.
 dnl
 dnl The basis for this file was generated by autoscan(1) [pere 1998-03-19]
 dnl
+dnl $Id$
 
 AC_INIT(Simulator/Aircraft/aircraft.cxx)