> From: Fabrice Popineau <fabrice.popineau@gmail.com>
> Date: Sat, 28 Oct 2017 19:59:20 +0200
> Cc: Emacs developers <emacs-devel@gnu.org>
>
> I configure with --prefix=/mingw64
> and everything under /mingw64/bin has been erased

Can you spot the Makefile rule or command that does/did this?
Maybe I'm blind, but I couldn't find it.