* src/ntbtls-cli.c: Include errno.h.
(w32_cookie_read) [W32]: New.
(w32_write_server) [W32]: New.
(w32_cookie_write) [W32]: New.
(w32_cookie_functions) [W32]: New.
(connect_estreams) [W32]: Use es_fopencookie.
(main) [W32]: Init Winsock.