3 ways. All quite ugly:
16:45 < hendry> bilbo$ ls 16:45 < hendry> flyspray_0.9.5-1.diff.gz flyspray_0.9.5.orig.tar.gz tar zxvf cd gunzip -c ../flyspray_0.9.5-1.diff.gz | patch -p1
dpkg-source, but then you also need the fucking .dsc:
wget http://amaretto.inria.fr:8080/~mc/flyspray/flyspray_0.9.5-1.dsc dpkg-source -x flyspray_0.9.5-1.dsc
And then uupdate. Sweet jesus.
18:57 < Viiru> hendry: You need both the upstream tarball (modified to be like a debian orig.tar.gz) and the debianized version unpacked. Then run uupdate in the debianized sourcedir like uupdate ../newupstream.tar.gz and the magic should happen. 18:57 < Viiru> But since I'm drunk, I wont make any guarantees. 18:58 < hendry> :) 18:59 < Viiru> It really is a very simple tool.