bug#65326: Alt-x prefix does not work on NetBSD/OpenBSD console

[Bruno Haible]

With Emacs I'm used to type M-x as Alt-x (left Alt key). But this does not
work in the NetBSD 9.3 console and the OpenBSD 7.2 console. As a result, I
have to use ESC-x instead, which breaks a convenient habit.

How to reproduce:

1. Log in at the NetBSD or OpenBSD console.
   $TERM is wsvt25 on NetBSD, or vt220 on OpenBSD.

2. Edit some file:
$ src/emacs ~/hello.c
<Down>
<RET>
<M-x> (Alt-x) does not work as expected: It inserts a 'x'.

Bruno