bug#5792: 23.1; man.el{,c} fails to load when utf-8 mode enabled

[Chong Yidong]

> In my .emacs, I have:
>
>   (set-terminal-coding-system 'utf-8)
>   (set-keyboard-coding-system 'utf-8)
>
> When I invoke M-x man, I get an invalid byte when trying to load
> either the man.el or the man.elc.

Thanks for the bug report, but it's took vague for me to reproduce; for
instance, what do you mean by "get an invalid byte"?  Could you provide
a testcase starting from `emacs -Q'?