emchain libc mismatch for powerpc

[Brendan Simon <Brendan@BrendanSimon.com>]

   emchain: Error.  Mismatch in source versions
   powerpc does not appear to have build 2.7-6 of libc successfully.
   ...
   Only version 2.7-9 is available on powerpc and emchain is unable to
   proceed.

Is there a way to tell emchain to use libc6 2.7-9, and ignore libc6 
2.7-6 ???

Is this error because I am running a testing distribution, but trying to 
build emdebian cross tools from unstable sources ??

If so, does this mean that the only way to build emdebian cross tools is 
to run an unstable distribution?

I don't really want to do that.  I'm happy to fight with testing, but 
not unstable.  I'm having enough problems with X on testing as it is.

NOTE: I'm trying to build the powerpc cross tools, to help debug and fix 
them so we can get them back into emdebian :)

Thanks,
Brendan.