[gssdp] client: Add missing prototype for get_address_mask

[Jens Georg <jensgeorg src gnome org>]

commit a6d25cef5645bdb45e90a7a17e280b69eab63d01
Author: Jens Georg <mail jensge org>
Date:   Tue Jun 16 22:55:28 2020 +0200

    client: Add missing prototype for get_address_mask

 libgssdp/gssdp-client.h | 3 +++
 1 file changed, 3 insertions(+)
---
diff --git a/libgssdp/gssdp-client.h b/libgssdp/gssdp-client.h
index 70c5887..1b1308e 100644
--- a/libgssdp/gssdp-client.h
+++ b/libgssdp/gssdp-client.h
@@ -98,6 +98,9 @@ gssdp_client_get_index        (GSSDPClient *client);
 GSocketFamily
 gssdp_client_get_family       (GSSDPClient *client);
 
+GInetAddressMask *
+gssdp_client_get_address_mask (GSSDPClient *client);
+
 void
 gssdp_client_append_header    (GSSDPClient *client,
                                const char  *name,