bug#45303: #45303 [feature/native-comp] building error on Windows

[Eli Zaretskii]

> From: Andy Moreton <andrewjmoreton@gmail.com>
> Date: Sat, 19 Dec 2020 14:35:45 +0000
> 
> b) Linker error for "strsignal"
>    This seems to be a configure problem. On master the configure test
>    for strsignal fails to link, and the gnulib replacement get used.
>    On the native branch the configure test links successfully, so the
>    gnulib replacement does not happen. The only difference in the
>    conftest command line appears to be adding libgccjit, so somehow
>    that library is providing a strsignal symbol.
>    Adding "ac_cv_func_strsignal=no" in nt/mingw-cfg.site appears to
>    suppress this problem, but I don't know if that is the right fix.

I must be missing something, because I don't see strsignal used on
master in the MinGW build at all.  Moreover, Gnulib's strsignal.c is
not even in lib/.  We call sigdescr_np instead.  So I wonder how did
you see that the Gnulib replacement for strsignal is used on master in
the Windows build.