On 24-03-2019 20:21, Ron Tarrant wrote:

sudo apt install dmd-bin

I think you mean apt-get here, and you may also want to install gtkD
from the d-apt.

If you install gtkD from the d-apt the gtkd files will probably be
installed in /usr/lib/ and /usr/include/dlang/ you can inspect the
output of pkg-config --cflags --libs gtkd-3 to get the exact locations.

.dub is the location where dub stores the libraries it has build as