Subject: bug#57386: 29.0.50; support make-symbolic-link without admin priviledge on Windows

From: Kiên Nguyễn Quang <[email-masked]>
Date: Thu, 25 Aug 2022 00:33:58 +0900

The CreateSymbolicLink Win32API has a flag that allows creating sym-links
without admin privileges SYMBOLIC_LINK_FLAG_ALLOW_UNPRIVILEGED_CREATE.
This patch added that support for w32 Emacs.