server: fix function prototypes

Several functions in server/ were not specifying an argument list,
ie they were declared as void foo(); When compiling with
-Wstrict-prototypes, this leads to:
test_playback.c:93:5: erreur: function declaration isn’t a prototype
[-Werror=strict-prototypes]

1 files changed, 1 insertions, 1 deletions

diff --git a/server/red_channel.h b/server/red_channel.h
index a24ff7db..2ebb6b63 100644
--- a/server/red_channel.h
+++ b/server/red_channel.h
@@ -433,7 +433,7 @@ struct RedClient {
     int disconnecting;
 };
 
-RedClient *red_client_new();
+RedClient *red_client_new(void);
 MainChannelClient *red_client_get_main(RedClient *client);
 // main should be set once before all the other channels are created
 void red_client_set_main(RedClient *client, MainChannelClient *mcc);