If you want to use gtk-fortran as a fpm dependency, you just need: A modern Fortran compiler (>= Fortran 2008 standard), for example gfortran, ifort, ifx... GTK and the associated development files.
Earlier this year Ubuntu announced plans to replace document viewer app Evince with Papers, a modern GTK4/libadwaita fork 1 of the former, in Ubuntu 25.04—today, the swap was made official. Ubuntu ...