Merge lp://staging/~vorlon/ubuntu/natty/eglibc/multiarch-support into lp://staging/ubuntu/natty/eglibc

Currently, trying to install any foreign arch libraries with apt will fail with this error:

  E: Couldn't configure pre-depend multiarch-support for libgcc1, probably a dependency cycle.

This is correct behavior on the part of apt. libc6 Provides: multiarch-support, libgcc1 Pre-Depends: multiarch-support, libc6 Depends: libgcc1.

The proposed branch will break this dependency loop for foreign arch packages by making 'multiarch-support' a real, Multi-Arch: foreign package depending on the native libc to satisfy these dependencies. I believe this should have no effect on the native system, which avoids this dependency loop by having the necessary libraries installed before apt is ever called; and I believe it's safe for foreign architectures because a) there's no way you're getting a foreign libc unpacked, *period*, unless it's already Multi-Arch: same, and there should be no libc package that's Multi-Arch: same that doesn't also support the multiarch paths; and b) it's the foreign arch, so if I'm wrong about this there's no danger to the package manager's integrity (you can't cross-grade the base system yet).

But it's late in the cycle and this is a new (if contentless) binary package being added to the base system, so I'm requesting the release team's review before landing this change.