PATCH [libiberty]: fix psignal prototype

[DJ Delorie]

> Okay for the trunk?
> 
> 
> 2007-01-31  Ben Elliston  <bje@au.ibm.com>
> 
>         * strsignal.c (psignal): Change type of signo to int.
>         * functions.texi: Regenerate.

Ok.