On 10-03-2020 17:57, Russel Winder wrote:

You do not mention which platform you are working on. For me using Debian Sid, GtkD is an installable package and so all I need is:

dependency('gtkd-3', version: '>= 3.9.0')

having installed the package libgtkd-3-dev.

This doesn't perhaps answer your question, but it hopefully starts a conversation that can end with an answer to your question.

It looks like the meson dub integration has issues with sub projects,
since the files and libraries mentioned in the errors aren't part of
gtk-d:gtkd, but part of the other sub projects.

If gtkd is available in the repositories of your that that can be used
as a regular dependency in meason. The same is also true is you install
gtkd manually with make && make install.