bug#47196: 28.0.50; Build failed on MinGW64

[M. Weber]

The revision listed below was the last i was able to build. Since then,
or a few commits later, it fails because the command

> ./temacs --batch  -l loadup --temacs=pbootstrap

returns a non-zero status, i guess.

Here are the last lines of make's output:

> ...
> cp -f temacs.exe bootstrap-emacs.exe
> rm -f bootstrap-emacs.pdmp
> ./temacs --batch  -l loadup --temacs=pbootstrap
> Loading loadup.el (source)...
> Dump mode: pbootstrap
> Using load-path (<lisp-dirs> ...)
> Loading emacs-lisp/byte-run (source)...
> Loading emacs-lisp/backquote (source)...
> Loading subr (source)...
> Loading version (source)...
> Loading widget (source)...
> Loading custom (source)...
> make[1]: *** [Makefile:794: bootstrap-emacs.pdmp] Error 127
> make[1]: Leaving directory '<path-to-emacs>/src'
> make: *** [Makefile:411: src] Error 2

Many thanks!

In GNU Emacs 28.0.50 (build 1, x86_64-w64-mingw32)
 of 2021-03-08 built on <host-name>
Repository revision: a190bc9f3067d9c35fc4344248222eb6ff2a0fc6
Repository branch: master
Windowing system distributor 'Microsoft Corp.', version <10.0...>
System Description: Microsoft Windows 10 Pro (v10.0...)

Configured features:
ACL DBUS GIF GMP GNUTLS HARFBUZZ JPEG JSON LCMS2 LIBXML2 MODULES NOTIFY
W32NOTIFY PDUMPER PNG RSVG SOUND THREADS TIFF TOOLKIT_SCROLL_BARS XPM
ZLIB

Important settings:
  value of $LANG: ENU
  locale-coding-system: cp1252