How do I apply a patch Debian style?

[Joost Kraaijeveld <J.Kraaijeveld@Askesis.nl>]

Hi,

I want to compile stock gnome-system-monitor-2.8.1-2 with a patch
gnome-system-monitor-2.8.1-4.diff.gz applied.

How do I do that? What do I need, more than a compiling
gnome-system-monitor-2.8.1-2 and the
gnome-system-monitor-2.8.1-4.diff.gz?

Is there a Debian way of doing things, so that I end up with a
gnome-system-monitor-2.8.1-4_amd64.deb package that I can install?

-- 
Groeten,

Joost Kraaijeveld
Askesis B.V.
Molukkenstraat 14
6524NB Nijmegen
tel: 024-3888063 / 06-51855277
fax: 024-3608416
e-mail: J.Kraaijeveld@Askesis.nl
web: www.askesis.nl