The "inno_setup" build target will set up the "inno_setup_build"
directory containing the ISS script for Inno Setup (>= 6.4).

You will need some unofficial language files listed in
inno_setup_languages.isi. Download them from the Inno Setup website or
source code repository (Files/Languages/Unofficial/) to the
"Languages/Unofficial/" directory in the root of your Inno Setup
installation.
