--- IO-AIO/gendef0	2012/04/06 11:39:25	1.1
+++ IO-AIO/gendef0	2014/01/25 00:15:52	1.2
@@ -6,6 +6,11 @@
 open STDOUT, ">def0.h"
    or die "def0.h: $!";
 
+print <<EOF;
+/* GENERATED FILE */
+/* use ./gendef0 to regenerate this file */
+EOF
+
 while (<>) {
    if (/^\s*const_iv\s*\((\S+)\)\s*$/ || /^\s*const_niv\s*\([^,]+,\s*(\S+)\)\s*$/) {
       print "#ifndef $1\n",