Fixed with share/mk/bsd.prog.mk rev. >= 1.153.

> Hi all
> 
> while building today's -current (or yesterday) I get:
> 
> building standard sa library
> /usr/toolchain/bin/i386--netbsdelf-ranlib libsa.a
> making sure the z library is up to date...
> cd: can't cd to /usr/src/sys/arch/i386/stand/biosboot/obj.i386/lib/z
> *** Error code 2
> 
> Stop.
> nbmake: stopped in /usr/src/sys/arch/i386/stand/biosboot
> 
> Is current broken or my system is not ok?
> 
> Thanks (please CC to my email address).
> 
> --
> Of course it runs NetBSD - http://www.netbsd.org
> Julio Merino (Slink) <juli@merino.net>

-- 
Juergen Hannken-Illjes - hannken@eis.cs.tu-bs.de - TU Braunschweig (Germany)