Unexec dumping results in "Segmentation fault" on Windows Msys2

[Nikolay Kudryavtsev]

Hello. Whenever I try to build emacs-27 branch using msys2 
--with-dumping=unexec I get:

make[2]: *** [Makefile:296: 
/d/Emacs/source/repo/lisp/emacs-lisp/macroexp.elc] Segmentation fault
make[2]: *** Waiting for unfinished jobs....
make[2]: *** [Makefile:296: 
/d/Emacs/source/repo/lisp/emacs-lisp/byte-opt.elc] Segmentation fault
make[2]: *** [Makefile:296: 
/d/Emacs/source/repo/lisp/emacs-lisp/autoload.elc] Segmentation fault
make[2]: *** [Makefile:296: 
/d/Emacs/source/repo/lisp/emacs-lisp/cconv.elc] Segmentation fault
make[2]: *** [Makefile:296: 
/d/Emacs/source/repo/lisp/emacs-lisp/bytecomp.elc] Segmentation fault

This only happens with the repository version. I've tried "make 
extraclean" and other clean targets, they did not help.

With the source archive it's different in that Emacs compiles fine, but 
it immediately crashes silently when you run it. That's actually the 
other problem I'm trying to debug, since I'm trying to find a way to get 
Emacs 26 to compile on Msys2 again and I'm observing the same 
Segmentation faults for any unexec Emacs versions from the repo. So this 
seems like a problem with some newer Msys2 package.

Could not test the master branch since trying to build it results in:

D:/Emacs/source/repo/src/pdumper.c: In function 'thaw_hash_tables':
D:/Emacs/source/repo/src/pdumper.c:5472:30: error: 'pdumper_hashes' 
undeclared (first use in this function); did you mean 'pdumper_hook'?
 5472 |   Lisp_Object hash_tables = *pdumper_hashes;
      |                              ^~~~~~~~~~~~~~
      |                              pdumper_hook