Getting GTK-Doc

python 2/3 - the main scripts are written in python.

xsltproc - the xslt processor from libxslt xmlsoft.org/XSLT/

docbook-xsl - the docbook xsl stylesheets sourceforge.net/projects/docbook/files/docbook-xsl

One of source-highlight, highlight or vim - optional - used for syntax highlighting of examples