[Bug-readline] readline 7.0 breaks interactive non ASCII input

[Steven Penny]

With readline 6.3 on Windows, you could type Alt 234 and it would produce
GREEK CAPITAL LETTER OMEGA U+03A9. However with readline 7.0 it yields nothing.
Non ASCII characters can be read from scripts, but they cannot be entered
interactively.

They cannot be pasted either; pasting some words will remove all non ASCII
characters. I did a git bisect on the readline-7.0-testing branch and came up
with this:

    ef27d114778ffef483ed2746603f9487f880edbd is the first bad commit
    commit ef27d114778ffef483ed2746603f9487f880edbd
    Author: Chet Ramey <address@hidden>
    Date:   Thu Jul 9 16:28:21 2015 -0400

        readline-7.0-alpha distribution

http://git.savannah.gnu.org/cgit/readline.git/commit?id=ef27d11

at -9728/+13220, it is not super helpful.