Install pkg-create-dbgsym in build chroots

[broder]

pkg-create-dbgsym diverts and wraps dh_strip to create an extra .ddeb for any binary package that has debugging symbols to strip. It's used by Ubuntu to generate  http://ddebs.ubuntu.com/

This seems like a pretty harmless way to get some potential extra testing capabilities. We'll have to cross-port the package for Debian, since it's still Ubuntu-specific, but I suspect that will just be a matter of rebuilding the package.

[broder]

I guess one potential concern would be that I have no idea what reprepro will do it you try to give it ddebs. That might be worth finding out before we start force-feeding them down its throat.

[broder]

From some quick experimentation, it looks like pkg-create-dbgsym creates the .ddebs, but doesn't add them to the .changes file, which means that sbuild drops them on the floor and they get lost in the ephemeral chroot.

[tabbott]

I don't really see us actually using .ddebs that provide debugging symbols very often.

But it could be fun to work on getting this feature into Debian and supported by sbuild.