Installing the current emacs-28 branch under Windows 10

[H. Dieter Wilhelm]

Hello Emacs

I'm trying to compile the latest emacs-28 branch (which is compiling
under GNU-Linux). I adhered exactly to the recipes of
etc/nt/INSTALL.W64. But I'm already at the end of my tether.  What would
you do in below situation?

Thanks for your support

       Dieter
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uidg1626@VSL7V7PW MINGW64 /d/Emacs/emacs
$ ./autogen.sh
Checking whether you have the necessary tools...
(Read INSTALL.REPO for more details on building Emacs)
Checking for autoconf (need at least version 2.65) ... ok
Your system has the required tools.
Building aclocal.m4 ...
Running 'autoreconf -fi -I m4' ...
' is already registered with AC_CONFIG_FILES.
../autoconf-2.71/lib/autoconf/status.m4:289: AC_CONFIG_FILES is expanded from...
configure.ac:6010: the top level
autom4te: error: /usr/bin/m4 failed with exit status: 1
autoreconf: error: /usr/bin/autoconf failed with exit status: 1

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-- 
Best wishes
H. Dieter Wilhelm
Zwingenberg, Germany