[pacman-dev] xdelta support in pacman 3.x

Hello all, I reckon it would be great to download only diffs for new package versions instead of the whole enchilada every time a buffer overflow exploit is fixed in kernel26. Building on Thikasabrik's good work on the forum (see http://bbs.archlinux.org/viewtopic.php?id=22872) I have come up with the attached patch for makepkg. FYI, I intend to look further into the pacman side of things next up. I hope I can make this thing work... Comments & suggestions are welcome... Regards Dale