I've made the licence text, the About box, and the host key dialog
into GTK selectable edit controls. (The former because it contains a
lot of text; the About box because pasting version numbers into bug
reports is obviously useful; the host key because of the fingerprint.)
(cherry picked from commit 21101c7397e460933635a7bfed813864fc4f88fe)
Conflicts:
unix/gtkdlg.c
unix/unix.h
(cherry-picker's notes: not a trivial resolution, since I had to apply
the equivalent changes in the pre-GTK3-port version of the code)