trying to build alpha cross-compiler

I'm trying to build an alpha cross-compiler but having problems.  I managed
to build an armhf cross-compiler under wheezy using the directions at
http://gsoc.sitedethib.com/, but when building an alpha cross-compiler under
sid/unstable (since up-to-date alpha is only available on sid) and trying
to install the libc developer files to build the cross gcc I hit the
following package conflict:

 libc6.1-dev:alpha : Conflicts: libc6-dev but 2.13-38 is installed.
 libc6-dev : Conflicts: libc6.1-dev:alpha but 2.13-38 is to be installed.

That is, on the host (amd64) libc6-dev is only available but on the target
(alpha) it is libc6.1-dev and there is a conflict specified in both packages
between libc6-dev and libc6.1-dev so I can't get both installed.

Is there some way I can get both libc6-dev (amd64) remaining installed (so
I have a working host!) and get libc6.1-dev:alpha installed so I can build
the cross-compiler?

Cheers
Michael