Make server_connect_to() return a bool

The resulting socket is accessible from the server instance, there is no
need to return it.

This paves the way to use several sockets in parallel.

app/src/scrcpy.c

@@ -290,13 +290,14 @@ scrcpy(const struct scrcpy_options *options) {
         goto finally_destroy_server;
     }
 
-    socket_t device_socket = server_connect_to(&server);
+    if (!server_connect_to(&server)) {
-    if (device_socket == INVALID_SOCKET) {
         server_stop(&server);
         ret = false;
         goto finally_destroy_server;
     }
 
+    socket_t device_socket = server.device_socket;
+
     char device_name[DEVICE_NAME_FIELD_LENGTH];
     struct size frame_size;
 

app/src/server.c

@@ -219,7 +219,7 @@ server_start(struct server *server, const char *serial,
     return true;
 }
 
-socket_t
+bool
 server_connect_to(struct server *server) {
     if (!server->tunnel_forward) {
         server->device_socket = net_accept(server->server_socket);
@@ -231,7 +231,7 @@ server_connect_to(struct server *server) {
     }
 
     if (server->device_socket == INVALID_SOCKET) {
-        return INVALID_SOCKET;
+        return false;
     }
 
     if (!server->tunnel_forward) {
@@ -243,7 +243,7 @@ server_connect_to(struct server *server) {
     disable_tunnel(server); // ignore failure
     server->tunnel_enabled = false;
 
-    return server->device_socket;
+    return true;
 }
 
 void

app/src/server.h

@@ -40,7 +40,7 @@ server_start(struct server *server, const char *serial,
              const char *crop, bool send_frame_meta);
 
 // block until the communication with the server is established
-socket_t
+bool
 server_connect_to(struct server *server);
 
 // disconnect and kill the server process