Grab both the "orig" tarball and one of the matching "debian" tarballs from http://ppa.launchpad.net/terry.guo/gcc-arm-embedded/ubuntu/pool/main/g/gcc-arm-none-eabi/
I've used the "precise" one, as that's reasonably old and should work on Debian.
Untar the orig tarball, cd into the resulting directory, then untar the "debian" tarball. This will result in a nice debian/
directory.
You can change the changelog if you want with dch
.
Then just build it dpkg-buildpackage -uc -us -sa
When the build is complete, you'll find your nice debian package one level up, just like usual. Successfully built the 4.9.3-2015q3 release using the "precise" debian tarball for Wheezy amd64.