Add the mingw and msys2 tools to the path

scripts/site-start.el

@@ -1,8 +1,11 @@
 (let* ((emacs-libexec-path (car (last exec-path)))
        (emacs-libexec-ndx (string-match "libexec" emacs-libexec-path))
-       (emacs-root (substring emacs-libexec-path 0 emacs-libexec-ndx)))
-  (add-to-list 'exec-path (expand-file-name "bin/" emacs-root))
-  (add-to-list 'exec-path (expand-file-name "usr/bin/" emacs-root))
+       (emacs-root (substring emacs-libexec-path 0 emacs-libexec-ndx))
+       (msys2-dir (expand-file-name "usr/bin/" emacs-root))
+       (mingw-dir (expand-file-name "bin/" emacs-root)
+  (add-to-list 'exec-path msys2-dir)
+  (add-to-list 'exec-path mingw-dir)
+  (setenv "PATH" (concat mingw-dir ";" msys2-dir ";" (getenv "PATH")))
   (let ((default-directory (expand-file-name "usr/share/emacs/site-lisp/" emacs-root)))
     (when (file-exists-p default-directory)
       (if (fboundp 'normal-top-level-add-subdirs-to-load-path)