Handle non-ASCII tun device names under Windows
Handle non-ASCII tun device names under Windows

Most of the calls here can remain resolutely ASCII-only, since the registry
key names aren't going to contain arbitrary characters. The cosmetic device
name, on the other hand, does need to be obtained as "Unicode" and converted
to UTF-8.

We can't just use WideCharToMultiByte here because it doesn't exist on
older versions of Windows (yay!).

Signed-off-by: David Woodhouse <b460d66aaf00c296a3db1c1d9eeafc081d5f7d70@intel.com>

chadcatlett/openconnect,brandt/openconnect,lins05/openconnect,mveplus/openconnect-client,nmav/openconnect-mine,liiir1985/openconnect,nmav/openconnect-mine,don-johnny/openconnect,mtmiller/openconnect,don-johnny/openconnect,chadcatlett/openconnect,don-johnny/openconnect,cernekee/openconnect,brandt/openconnect,lins05/openconnect,brandt/openconnect,liiir1985/openconnect,atyndall/openconnect,mveplus/openconnect-client,cernekee/openconnect,lins05/openconnect,brandt/openconnect,mtmiller/openconnect,atyndall/openconnect,atyndall/openconnect,chadcatlett/openconnect,liiir1985/openconnect,nmav/openconnect-mine,liiir1985/openconnect,mveplus/openconnect-client,matlockx/openconnect,mveplus/openconnect-client,matlockx/openconnect,matlockx/openconnect,cernekee/openconnect,matlockx/openconnect,don-johnny/openconnect,nmav/openconnect-mine,atyndall/openconnect,cernekee/openconnect,chadcatlett/openconnect,mtmiller/openconnect,lins05/openconnect,mtmiller/openconnect