Compilation of rust-demangle.c fails on MinGW

[Eli Zaretskii]

> Date: Wed, 4 Aug 2021 14:03:21 +0100
> From: Jonathan Wakely <jwakely@redhat.com>
> Cc: gcc-bugs@gcc.gnu.org
> 
> In GCC's bugzilla.

That's what I tried originally, but there's no libiberty there among
the various "components".  So I decided the GCC Bugzilla was not the
right place.  If it is the right place, please tell which component to
select.  Maybe "other"?  (But it's confusing that libiberty is not in
the list.)

Thanks.