diff --git a/lib/sl/lex.l b/lib/sl/lex.l
index 1092d5d1f..23202783e 100644
--- a/lib/sl/lex.l
+++ b/lib/sl/lex.l
@@ -1,6 +1,6 @@
 %{
 /*
- * Copyright (c) 1998 - 2000 Kungliga Tekniska Högskolan
+ * Copyright (c) 1998 - 2001 Kungliga Tekniska Högskolan
  * (Royal Institute of Technology, Stockholm, Sweden). 
  * All rights reserved. 
  *
@@ -44,6 +44,8 @@ static int getstring(void);
 
 #define YY_NO_UNPUT
 
+#undef ECHO
+
 %}