I updated ncurses to ncurses-5.2-2. Now, when I start emacs I get a warning message: emacs: Symbol `ospeed' has different size in shared object, consider re-linking
Sorry, this is probably the upgrade to glibc-2.2-5 wich causes the problem, not ncurses.
This would be an ncurses problem.
emacs is built against a slightly different ncurses version. It needs rebuilding.
ncurses should be compatible through 7.x, anything else is a bug (emacs was rebuilt for other reasons anyway, but this is a bug in ncurses.
No, emacs got built against the incompatible version. That's why it needs/needed rebuilding. In any case, it should be rebuilt by now.
It is - including emacs-20.7-23, coming to Rawhide soonish (some earlier ones are also rebuilt)