serve: mark unused parameters in virtual functions

Each v2 "serve" action has a virtual function for advertising and
implementing the command. A few of these are so trivial that they don't
need to look at their parameters, especially the "repository" parameter.
We can mark them so that -Wunused-parameter doesn't complain.

Note that upload_pack_v2() probably _should_ be using its repository
pointer. But teaching the functions it calls to do so is non-trivial.
Even using it for something as simple as reading config is tricky, both
because it shares code with the v1 upload pack, and because the
git_protected_config() mechanism it uses does not have a repo-specific
interface. So we'll just annotate it for now, and cleaning it up can be
part of the larger work to drop references to the_repository.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

serve.c

@@ -12,13 +12,13 @@
 static int advertise_sid = -1;
 static int client_hash_algo = GIT_HASH_SHA1;
 
-static int always_advertise(struct repository *r,
-			    struct strbuf *value)
+static int always_advertise(struct repository *r UNUSED,
+			    struct strbuf *value UNUSED)
 {
 	return 1;
 }
 
-static int agent_advertise(struct repository *r,
+static int agent_advertise(struct repository *r UNUSED,
 			   struct strbuf *value)
 {
 	if (value)
@@ -34,7 +34,7 @@ static int object_format_advertise(struct repository *r,
 	return 1;
 }
 
-static void object_format_receive(struct repository *r,
+static void object_format_receive(struct repository *r UNUSED,
 				  const char *algo_name)
 {
 	if (!algo_name)
@@ -57,7 +57,7 @@ static int session_id_advertise(struct repository *r, struct strbuf *value)
 	return 1;
 }
 
-static void session_id_receive(struct repository *r,
+static void session_id_receive(struct repository *r UNUSED,
 			       const char *client_sid)
 {
 	if (!client_sid)

upload-pack.c

@@ -1699,7 +1699,7 @@ enum fetch_state {
 	FETCH_DONE,
 };
 
-int upload_pack_v2(struct repository *r, struct packet_reader *request)
+int upload_pack_v2(struct repository *r UNUSED, struct packet_reader *request)
 {
 	enum fetch_state state = FETCH_PROCESS_ARGS;
 	struct upload_pack_data data;