message: [vcpkg] Fix build on Windows 8.1 SDK
diff: @@ -141,7 +141,12 @@ namespace vcpkg::Files
  const auto target = read_symlink_implementation(oldpath, ec);
  if (ec) return;
  - const DWORD flags = SYMBOLIC_LINK_FLAG_ALLOW_UNPRIVILEGED_CREATE;
  + const DWORD flags =
  +#if defined(SYMBOLIC_LINK_FLAG_ALLOW_UNPRIVILEGED_CREATE)
  + SYMBOLIC_LINK_FLAG_ALLOW_UNPRIVILEGED_CREATE;
  +#else
  + 0;
  +#endif
  if (!CreateSymbolicLinkW(newpath.c_str(), target.c_str(), flags))
  {
  const auto err = GetLastError();
  