sh tab completion missing

["Jeremy C. Reed" <reed%reedmedia.net@localhost>]

I didn't see any src/external/Makefile. Then realized it was just tab 
completion that was broken:

xen-netbsd-5-amd64-1# cd /chroot-netbsd-5/usr/src/
xen-netbsd-5-amd64-1# ls external/ <-- I Pressed TAB TAB here
external/apache2         external/bsd            
external/cddl            external/CVS            
external/gpl2            external/gpl3           
external/ibm-public      external/intel-fw-eula  
external/intel-fw-public external/intel-public   
xen-netbsd-5-amd64-1# ls external/

xen-netbsd-5-amd64-1# ident /bin/sh | grep 2010
     $NetBSD: cd.c,v 1.40 2010/01/01 19:34:59 dholland Exp $
     $NetBSD: eval.c,v 1.100 2010/06/03 16:14:13 christos Exp $
     $NetBSD: main.c,v 1.56 2010/02/21 09:54:57 christos Exp $

Looks like tab completion sometimes works if in different directories or 
different base directory used.