I've changed the commands a little bit from http://mosquitto.org/2012/11/making-mosquitto-packages-for-debian-yourself/ to be more faithful to my own style. Edit your /etc/apt/sources.list so that it has both stable and testing e.g.
deb http://ftp.au.debian.org/debian stable main deb http://ftp.au.debian.org/debian testing main
and edit /etc/apt/preferences
Package: * Pin: release a=stable Pin-Priority: 990 Package: * Pin: release a=testing Pin-Priority: 800
Followed by
sudo apt-get update sudo apt-get install build-essential python quilt libwrap0-dev libssl-dev devscripts python-setuptools sudo apt-get install libssl-dev=1.0.1c-4 python3
Then
mkdir ~/tmp cd ~/tmp wget http://mosquitto.org/files/source/mosquitto-1.0.5.tar.gz -O mosquitto_1.0.5.orig.tar.gz tar xvf mosquitto-1.0.5.orig.tar.gz cd mosquitto-1.0.5/ wget http://mentors.debian.net/debian/pool/main/m/mosquitto/mosquitto_1.0.5-1.debian.tar.gz tar xvf mosquitto_1.0.5-1.debian.tar.gz debuild -us -uc sudo dpgk -i ../*mosquitto*.deb
and you'll find the .debs in the parent folder.
Links to this page:
http://jtlog.wordpress.com/2013/01/04/raspberry-pi-mosquitto/
