bug#378: mesg is y in *shell*

[jidanni]

Odd, unlike all the other shells and windows on my computer,
M-x shell
$ mesg
is y
In xterm they are n. (However other users can't write(1) to the *shell*
buffer, y or n. I tested it with wall(1).)
P.S., (apropos (quote ("mesg")) nil) shows
  In this buffer, go to the name of the command, or function, or variable,
  and type RET to get full documentation.

  mesg
  nomesg
But RET does nothing.