The repositories here contain sources and binaries for the arm64 bootstrap in Debian (unstable) and Ubuntu (raring). There are both toolchain and tools packages for amd64 build machines and arm64 binaries built with them. And corresponding sources.
The packages have been built using multiarch methods.
Most of the work is being done in the Raring repo right now, due to the Debian freeze.
There are also armhf packages here used as controls for whether the arm64 M-A cross-build is expected to work.
Styatus of the ports is maintained here: http://wiki.debian.org/Arm64Port
Add these lines to use the sources and binaries here.
deb http://people.debian.org/~wookey/bootstrap/ubunturepo/ raring-bootstrap main universe deb-src http://people.debian.org/~wookey/bootstrap/ubunturepo/ quantal-bootstrap main universe
deb http://people.debian.org/~wookey/bootstrap/debianrepo/ debian-bootstrap main deb-src http://people.debian.org/~wookey/bootstrap/debianrepo/ debian-bootstrap main
You will need this key to have the archive authenticated: bootstrap-archive-key
The packages in here are not always newer than the ones in the main distro - to ensure they are preferentially used add the file /etc/apt/preferences.d/bootstrap
Package: * Pin: release n=quantal-bootstrap Pin-Priority: 1001
in your build chroot.