lablgtk dependency situation is unclear

[gdt]

This is a bug report about the README, essentially that I cannot understand what is going on. For background, I am the maintainer of unison which uses lablgtk(2) and is going to use lablgtk(3). This is a separate issue than #21.

It seems that this package can be built without lablgtk, and that results in the cairo bindings only. However the readme says that lablgtk is needed.

After building ocaml-cairo without lablgtk, I am able to build lablgtk3. While lablgtk3 does not document a dependency on ocaml-cairo, it fails to build without it.

Assuming the README is changed to say that lablgtk is optional and needed for ocaml-pango and ocaml-gtk, it should explain how one would choose whether to build those, particularly for packagers. It seems to be that lablgtk(2) and ttk2 in general are obsolete, and thus the gtk bindings in ocaml-cairo should not be built by default. I am unclear on the pango bindings, but if programs written for lablgtk3 work without them, then perhaps that is only of interest for programs written to use ocaml-cairo directly.

[gdt]

See also garrigue/lablgtk#151