Add return NULL; at end of thread loops.

gcc4.4 seem to think that this code is reachable but it isn't

src/iptv_input.c

@@ -158,6 +158,7 @@ iptv_thread(void *aux)
     }
     pthread_mutex_unlock(&iptv_recvmutex);
   }
+  return NULL;
 }
 
 

src/transports.c

@@ -832,6 +832,7 @@ transport_saver(void *aux)
     pthread_mutex_unlock(&global_lock);
     pthread_mutex_lock(&pending_save_mutex);
   }
+  return NULL;
 }