bug#24186: setlocale can't be localised

[Zefram]

I wrote:
>is my first time compiling a Guile myself.  It's failing on a missing
>library for which Debian supplies no package.

Turns out there was a package.  It was complaining about a lack of
"bdw-gc", and Debian doesn't have anything of that name, but it does
have it under the name "libgc".  So I've now got 2.1.3 running.

All of the code in my day-of-week-string-for-locale sketch works exactly
the same on 2.1.3 as it did on 2.0.

-zefram