Actually, the situation is a little more complicated and is probably my fault.
The problem was partly a side effect of the way in which I tried to set up gretl. I started with the repository version (1.8.1) which installed without problem. Then, I tried to update to 1.8.5 using the Debian version, but that didn't work. Finally, I compiled the whole program and ran "make install" which led to the problem I described. Now I have cleared everything out - including version 1.8.1 - and find that I have got gretlcli, but not gretl-x11. I suspect that the problem is some more missing libraries. What are the exact Gnome, GTK & GTK sourceview libraries required for the GUI version of gretl? By default, Ubuntu installs general libraries but not the dev versions. At the moment the configure output says that Gnome, GTK and GTKsourceview are not available. Gordon