Debian / Ubuntu Repository
To enable it, add repository sources:
$ sudo wget https://d-apt.googlecode.com/files/d-apt.list -O /etc/apt/sources.list.d/d-apt.list
then update local info and import d-apt public key:
$ sudo apt-get update && sudo apt-get --yes --allow-unauthenticated install d-apt-keyring && sudo apt-get update
Now you can install "GtkD for GTK+2":
$ sudo apt-get install libgtkd-1-dev libgtkd-1-doc
and "GtkD for GTK+3":
$ sudo apt-get install libgtkd-2-dev libgtkd-2-doc
More info: APT Repository for D
Compiling GtkD Applications
To compile GtkD applications for GTK+3:
$ dmd $(pkg-config --cflags --libs gtkd-2) my_gtkd_app.d