Split server stop() and join()

For consistency with the other components, call stop() and join()
separately.

This allows to stop all components, then join them all.

app/src/scrcpy.c

@@ -698,6 +698,10 @@ end:
         sc_file_pusher_destroy(&s->file_pusher);
     }
 
+    if (server_started) {
+        sc_server_join(&s->server);
+    }
+
     sc_server_destroy(&s->server);
 
     return ret;

app/src/server.c

@@ -909,7 +909,10 @@ sc_server_stop(struct sc_server *server) {
     sc_cond_signal(&server->cond_stopped);
     sc_intr_interrupt(&server->intr);
     sc_mutex_unlock(&server->mutex);
+}
 
+void
+sc_server_join(struct sc_server *server) {
     sc_thread_join(&server->thread, NULL);
 }
 

app/src/server.h

@@ -108,6 +108,10 @@ sc_server_start(struct sc_server *server);
 void
 sc_server_stop(struct sc_server *server);
 
+// join the server thread
+void
+sc_server_join(struct sc_server *server);
+
 // close and release sockets
 void
 sc_server_destroy(struct sc_server *server);