[Bug libstdc++/85494] implementation of random_device on mingw is useless

[dmjpp at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85494

--- Comment #3 from Dimitrij Mijoski <dmjpp at hotmail dot com> ---
Created attachment 44358
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=44358&action=edit
implements proper random_device for mingw-w64