bug#30788: 27.0.50; Getting 'char-displayable-p: Invalid hash table rehash size: 1.0' when starting emacs -Q

[Eli Zaretskii]

> Date: Tue, 13 Mar 2018 21:06:40 +0100
> Cc: 30788@debbugs.gnu.org,
>     mats.lidell@cag.se
> From: Ulrich Mueller <ulm@gentoo.org>
> 
> > Anyway, what does that have to do with fontconfig?  Emacs arranges
> > for LC_NUMERIC to be "C" at startup (see fixup_locale); does this
> > new versio0n of fontconfig somehow countermands that?
> 
> I believe that this line in function FcConfigEnsure is the culprit
> (present in 2.13.0 but not in 2.12.6):
> https://cgit.freedesktop.org/fontconfig/tree/src/fccfg.c?h=2.13.0#n52
> 
>         setlocale (LC_ALL, "");
> 
> Patching that code out fixes the problem here.

OK, thanks.  Can you tell when this code is called from Emacs?  I
don't see any direct calls to FcConfigEnsure in the sources.