Eliminate new warnings due to unused local variables noted in build testing.

graphics/vnc/server/vnc_negotiate.c

@@ -115,7 +115,6 @@ int vnc_negotiate(FAR struct vnc_session_s *session)
   ssize_t nsent;
   ssize_t nrecvd;
   size_t len;
-  int errcode;
 
 #ifdef CONFIG_NET_SOCKOPTS
   struct timeval tv;

graphics/vnc/server/vnc_receiver.c

@@ -92,7 +92,6 @@ int vnc_read_remainder(FAR struct vnc_session_s *session, size_t msglen,
 {
   ssize_t nrecvd;
   size_t ntotal;
-  int errcode;
 
   /* Loop until the rest of the message is recieved. */
 
@@ -136,7 +135,6 @@ int vnc_receiver(FAR struct vnc_session_s *session)
   struct timeval tv;
 #endif
   ssize_t nrecvd;
-  int errcode;
   int ret;
 
   DEBUGASSERT(session);
@@ -180,7 +178,7 @@ int vnc_receiver(FAR struct vnc_session_s *session)
 
       else if (nrecvd == 0)
         {
-          gwarn("WARNING: Connection closed\n", errcode);
+          gwarn("WARNING: Connection closed\n");
           return OK;
         }
 

sched/init/os_bringup.c

@@ -359,7 +359,7 @@ static inline void os_start_application(void)
                       CONFIG_BOARD_INITTHREAD_STACKSIZE,
                       (main_t)os_start_task, (FAR char * const *)NULL);
   DEBUGASSERT(pid > 0);
-
+  UNUSED(pid);
 #else
   /* Do the board/application initialization on this thread of execution. */