Missing snprintf in ucrt mingw + vc-refresh in find-file hook?

[Arthur Miller]

I am trying to compile Emacs on a new computer with freshly installed Windows 11
and mingw and having some troubles.

ld is complaining about missing snprintf. Seems like I can't get past that
one. I am using mingw ucrt toolchain/runtime since m4 failed for "ordinary"
mingw-w64 toolchain which I used on Windows 10 (m4 failed creating configure
script). Any idea why and what to do? It is defined in stdio.h so I would expect
it to be included in basic libc. Do I need to pass some extra flag
compiler/linker flag?

Since I removed msys mingw-w64 from my PATH to be sure mingw-w64-ucrt runtime
don't mix with other mingw runtime(s), Git also got removed from the path (I am
using mingw-64 one), and than my running Emacs couldn't open a file from a Git
repo.

The backtrace shows find-file is calling vc-refresh which realized I am in a Git
repo and is trying to call Git. If I start emacs -q afresh without Git in the
path, it works fine, so I assume Emacs registers Git program at some point and
does not check for it on every call, perhaps I am wrong about that one?

If that would be the case, I think it is a bug to assume that environment can't
change under running Emacs.

Also, calling vc-refresh obviously results in a quite expensive call to git
process everytime I open a file from git repo. Is it really a good default
option? At least I interpret it so since emacs -q has vc-refresh in
find-file-hook. Why do we even need vc-refresh by default in find-file-hook?

The backtrace:

  call-process("git" nil (t nil) nil "--no-pager" "ls-files" "-c" "-z" "--" 
"dired-auto-readme.el")
  process-file("git" nil (t nil) nil "--no-pager" "ls-files" "-c" "-z" "--" 
"dired-auto-readme.el")
  vc-git--call((t nil) "ls-files" "-c" "-z" "--" "dired-auto-readme.el")
  vc-git--out-ok("ls-files" "-c" "-z" "--" "dired-auto-readme.el")
  vc-git-registered("c:/Users/arthu/repos/dired-auto-readme/dired-auto-...")
  vc-git-registered("c:/Users/arthu/repos/dired-auto-readme/dired-auto-...")
  vc-call-backend(Git registered 
"c:/Users/arthu/repos/dired-auto-readme/dired-auto-...")
  #f(compiled-function (b) #<bytecode -0xf11085386c2ca6c>)(Git)
  mapc(#f(compiled-function (b) #<bytecode -0xf11085386c2ca6c>) (RCS CVS SVN 
SCCS SRC Bzr Git Hg))
  vc-registered("c:/Users/arthu/repos/dired-auto-readme/dired-auto-...")
  vc-backend("c:/Users/arthu/repos/dired-auto-readme/dired-auto-...")
  vc-refresh-state()
  run-hooks(find-file-hook)
  after-find-file(nil t)
  find-file-noselect-1(#<buffer dired-auto-readme.el> 
"~/repos/dired-auto-readme/dired-auto-readme.el" nil nil 
"~/repos/dired-auto-readme/dired-auto-readme.el" (0 3031117341))
  find-file-noselect("c:/Users/arthu/repos/dired-auto-readme/dired-auto-..." 
nil nil nil)
  find-file("c:/Users/arthu/repos/dired-auto-readme/dired-auto-...")
  dired--find-file(find-file 
"c:/Users/arthu/repos/dired-auto-readme/dired-auto-...")
  
dired--find-possibly-alternative-file("c:/Users/arthu/repos/dired-auto-readme/dired-auto-...")
  dired-find-file()
  funcall-interactively(dired-find-file)
  command-execute(dired-find-file)

After removing vc-refresh from find-file-hook, it works fine.

I am using 29.2_1 precompiled binary from the ftp, until I can compile my own.

/arthur