bug#5541: 23.1; after upgrading to emacs-23, meta key in xterm no longer works

[Chong Yidong <cyd@stupidchicken.com>]

Does anyone on this list have xterm-253 available to test?  I can't
reproduce the problem on xterm 241, and don't have xterm-253 available
to test at the moment.

> With "emacs23 -nw" running inside xterm-253, my meta key does not work
> for things like M-x.  Instead, the terminal bell beeps, and the string
> ;120~ appears in the buffer.  Looking at the log below, this is
> because the terminal actually sent the string \e[27;3;120~ which is
> occurring because emacs turned on the "modifyOtherKeys" setting with
> the escape sequence \e[>4;1m at startup.  Older versions of emacs did
> not do this, and everything worked fine.
>
> Indeed, if I execute the command:
>    (xterm-turn-off-modify-other-keys (selected-frame))
> then my meta key temporarily starts working again.
>
> My normal Xterm settings are
>   xterm*metaSendsEscape: true
>   xterm*eightBitInput: false
> which has always worked in previous versions.