* configure.in : Put check for getaddrinfo, inet_ntop and struture
          sockaddr_storage.

        * acconfig.h : Undefine ENABLE_IPV6

        * daemon/slave.c:
          (send_chosen_host): Used getaddrinfo to resolve the hostname.

        * daemon/choose.c:
          (gdm_choose_indirect_alloc) (gdm_choose_indirect_lookup):
          Changed prototype to have sockaddr_storage in place of sockaddr_in if
          IPv6 is enabled and changed the function accordingly.
          (gdm_choose indirect_lookup_by_chosen6): Function is added as a
          replacement of its IPv4 equivalent if IPv6 is enabled.
          (gdm_choose_direct_dispose)(gdm_choose_data): Changed for IPv6.

        * daemon/auth.c:
          (gdm_auth_secure_display): If IPv6 is enabled then we are dealing with
          IPv6 addresses. Used getaddrinfo for address resolution.

        * daemon/gdm.h: A field of type struct in6_addr is added to structure
          _GdmDisplay. In structure _GdmIndirectDisplay a field of type in6_addr
          is added and an existing field dsp_sa is changed to be of type
          sockaddr_storage if IPv6 is enabled on the system.
          _GdmForwardQuery structure will have members of type sockaddr_storage
          instead of sockaddr_in if IPv6 is enabled.
          Two new macros are defined for multicasting.

        * daemon/misc.c:
          (have_ipv6): Function added to check run-time IPv6 support.
          (gdm_get_free_display): We will deal with IPv6 address if
          IPv6 is enabled.
          (gdm_peek_local_address_list): Using getaddrinfo to generate the
          address list.
          (gdm_is_local_addr6)(gdm_is_loopback_addr6): These will be used with
          IPv6 addresses.
          For IPv4 addresses, continue to use their IPv4 counter parts.

        * daemon/xdmcp.c:
          (gdm_xdmcp_handle_forward_query), (gdm_xdmcp_handle_request),
          (gdm_xdmcp_handle_query), (gdm_xdmcp_handle_manage),
          (gdm_xdmcp_handle_managed_forward), (gdm_xdmcp_handle_got_managed),
          (gdm_xdmcp_handle_keepalive), (gdm_xdmcp_send_willing),
          (gdm_xdmcp_send_unwilling), (gdm_xdmcp_send_accept),
          (gdm_xdmcp_send_decline), (gdm_xdmcp_send_refuse ),
          (gdm_xdmcp_send_failed), (gdm_xdmcp_send_alive),
          gdm_xdmcp_send_managed_forward), (gdm_xdmcp_host_allow),
          (gdm_forward_query_alloc), (gdm_forward_query_lookup):
          All these functions will recieve sockaddr_storage type argument if
          IPv6 is enabled on the system.
          (gdm_xdmcp_whack_queued_managed_forwards6),
          (gdm_xdmcp_send_got_managed_forward6),
          (gdm_xdmcp_display_alloc6), (gdm_xdmcp_displays_from_host6),
          (gdm_xdmcp_displays_from_host6):
          All these functions are added to deal with IPv6 addresses.
          Their IPv4 equivalents will remain as it is.
          structure ManagedForward is changed to have sockaddr_storage field
          in place of sockaddr_in if IPv6 is enabled.
          (have_ipv6): Function added to check run-time IPv6 support.
          (gdm_xdmcp_init), (gdm_xdmcp_decode_packet):
          These functions are modified to deal with IPv6 addresses as well.

        * gui/gdmchooser.c:
          Structure _GdmChooserHost will have an added field of type in6_addr
          if IPv6 is enabled on the system.
          A global variable of type in6_addr is added.
          (gdm_chooser_host_alloc), (gdm_host_known), (is_loopback_addr),
          (gdm_addr_known), (gdm_chooser_decode_packet),
          (gdm_chooser_find_bcaddr), (do_ping),
          (gdm_chooser_xdmcp_discover), (gdm_chooser_add_hosts),
          (gdm_chbooser_xdmcp_init), (gdm_chooser_choose_host), (add_check),
          (gdm_chooser_add_host), (gdm_chooser_parse_config):
          Changed so that they all can deal IPv6 addresses.
          (gdm_chooser_find_mcaddr): Function added to set the multicast
          address.

        * gui/gdmXnestchooser.c:
          (have_ipv6): Added function to check for run time IPV6 support.
          (gte_free_display): Changed for IPv6.