libopenconnect: provide ability to use only wintun only windows
Currently libopenconnect on windows autodetects whether to use wintun or openvpn's TAP creating unpredictable behavior on openconnect-gui depending on whether openvpn is installed. To provide predictable and consistent behavior across systems for openconnect-gui libopenconnect should provide an option to use just wintun.
Related openconnect-gui#357 (closed)