[qw] Fix an extern in a C file

Rather worrying finding one. I guess I didn't feel like finding a header
for the declaration at time time.

qw/include/client.h

@@ -280,6 +280,8 @@ extern	struct cvar_s	*skin;
 
 extern	struct cvar_s	*cl_fb_players;
 
+extern struct cvar_s *hud_scoreboard_uid;
+
 extern	client_state_t	cl;
 
 extern	entity_t	*cl_entities[512];

qw/source/cl_main.c

@@ -216,7 +216,6 @@ jmp_buf     host_abort;
 
 char       *server_version = NULL;		// version of server we connected to
 
-extern cvar_t *hud_scoreboard_uid;
 static netadr_t cl_cmd_packet_address;
 
 static void

qw/source/cl_parse.c

@@ -172,8 +172,6 @@ int         cl_h_playerindex, cl_gib1index, cl_gib2index, cl_gib3index;
 
 int         packet_latency[NET_TIMINGS];
 
-extern cvar_t *hud_scoreboard_uid;
-
 int
 CL_CalcNet (void)
 {