Why are depends rebuilt on "bmake update" ?

[Dario Niedermann <dnied%tiscali.it@localhost>]

When I run 'bmake update' all the dependencies of the package I'm
updating are rebuilt, even if there aren't newer versions available.
Is there a way to avoid this?

Right now, pkgsrc is rebuilding probably half the system because I tried
to update 'tiff' (BTW, I had the latest version of 'tiff' installed, but
bmake didn't warn me that there were no further updates available for
that package, it just started rebuilding away).

A workaround I found so far is:

> pkg_delete -f foo
> cd /usr/pkgsrc/bar/foo
> bmake install
> pkg_admin rebuild-tree

Is this the way to go or is there a better recipe?

TIA


-- 
> head -n1 /etc/*-{version,release} && uname -mprs
Slackware 12.1.0
Linux 2.6.24.5-smp i686 AMD Turion(tm) 64 Mobile Technology MK-36