When looking at the current LICENSE file in the gtk-fortran GitHub repository, there is a copy of GPL 3, but no reference to the GCC Runtime Library Exception.
So if I understand the LICENSE file provided with the GTK-Fortran sourcecode correctly, a program that uses GTK Fortran has to be provided to third parties with the GPL3 or a compatible license. This means, for example, that the entire code of the program has to be open source and free (as in speech, not in beer) software.
Is this assumption correct? Of course the developers of GTK Fortran are completely free to chose the license for their work and I do not really have an opinion about to what extent there should be exceptions from the GPL.
I just wanted to know if and to what extent the exception is still valid.
I am currently not planning to publish a Fortran GUI project, so I am not directly affected but I think such a clarification would be interesting for people considering the use of GTK Fortran in their projects.