sudo apt-get build-dep swift
sudo apt-get install build-essential fakeroot devscripts

mkdir swift_build && cd swift_build
apt-get source swift
wget http://www.andrews-corner.org/patches/replicator_intersection_fix.diff
cd swift-2.5.0
patch -p1 < ../replicator_intersection_fix.diff

debchange -i

dpkg-source --commit

debuild -us -uc -i -I
sudo debi