dco-win: ensure the DCO API is not used when running on Windows

dco-win: ensure the DCO API is not used when running on Windows

On Windows the high level API should still use the link_socket object to
read and write packets. For this reason, even if dco_installed is true,
we still need to rely on the classic link_socket object.

Signed-off-by: Antonio Quartulli <a@unstable.cc>
Acked-by: Lev Stipakov <lstipakov@gmail.com>
Message-Id: <20220814085117.7128-1-a@unstable.cc>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg24929.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>