* fhandler_socket.cc (fhandler_socket::bind): Drop has_exclusiveaddruse

	* fhandler_socket.cc (fhandler_socket::bind): Drop has_exclusiveaddruse
	condition.  Fix comment about availability.  Move remaining comment to
	the right spot.  Drop has_ip_helper_lib condition.
	* net.cc (cygwin_setsockopt): Drop has_disabled_user_tos_setting
	condition.  Fix comment.
	(get_2k_ifs): Fix comment.
	(get_nt_ifs): Remove.
	(getifaddrs): Drop call to get_nt_ifs.
	(get_ifconf): Ditto.
	* wincap.cc: Throughout, drop has_ip_helper_lib,
	has_disabled_user_tos_setting, and has_exclusiveaddruse settings from
	wincaps.
	(wincap_unknown): Remove.
	(wincap_nt4): Remove.
	(wincap_minimal): New macro, set to wincap_nt4sp4 for now.
	(wincapc::init): Drop test for pre-SP4 NT4.  Just imply at least NT SP4.
	Replace references to wincap_unknown with references to wincap_minimal.
	* wincap.h (struct wincaps): Drop has_ip_helper_lib,
	has_disabled_user_tos_setting, and has_exclusiveaddruse flags and
	methods.