Apply by doing:
        cd /usr/src
        patch -p0 < 013_addusery2k.patch
	cd usr.sbin/adduser
	make
	make install

Index: usr.sbin/adduser/adduser.perl
===================================================================
RCS file: /cvs/src/usr.sbin/adduser/adduser.perl,v
retrieving revision 1.19
retrieving revision 1.20
diff -u -r1.19 -r1.20
--- usr.sbin/adduser/adduser.perl	1999/09/06 16:48:41	1.19
+++ usr.sbin/adduser/adduser.perl	2000/01/03 19:30:00	1.20
@@ -1057,9 +1057,10 @@
     return 1 if $logfile eq "no";
 
     local($sec, $min, $hour, $mday, $mon, $year) = localtime;
+    $year += 1900;
     $mon++;
 
-    foreach $e ('sec', 'min', 'hour', 'mday', 'mon', 'year') {
+    foreach $e ('sec', 'min', 'hour', 'mday', 'mon') {
 	# '7' -> '07'
 	eval "\$$e = 0 . \$$e" if (eval "\$$e" < 10);
     }