Can't run newly-compiled RELENG_6 programs under RELENG_6_1: missing __res_state

[M. Warner Losh]

In message: <20060719.181215.63038086.imp at bsdimp.com>
            "M. Warner Losh" <imp at bsdimp.com> writes:
: In message: <44BE8912.9010807 at palisadesys.com>
:             Guy Helmer <ghelmer at palisadesys.com> writes:
: : We just tried running programs under RELENG_6_1 that were compiled under 
: : RELENG_6 checked out 2006-07-19, and couldn't because of the undefined 
: : symbol "__res_state"l, which I would assume is a result of the recent 
: : MFC of the BIND 9 resolver library.    Is this to be expected?  It will 
: : cause a bit of a hassle...
: 
: It is not officially supported by the project.  You are running a
: binary compiled on a newer version of the system on an older version
: of the system.  This has sometimes worked in the past, but is outside
: the area that's expected to work.  There's been a number of breakages
: similar to this in past RELENG branches (there was one in 3.x and a
: lot on 4.x).
: 
: Having said that, can someone track down the problem in more detail to
: see if there might not be something we can do to mitigate the problem
: in the older versions?  What is __res_state?

Just saw Guy's followup note.

I'm unsure if we need a technological fix for this, or just a
documentation fix.  How common is it for programs to use the
semi-public interfaces that yours used?

Warner