Wait server from a separate thread

Create a thread just to wait for the server process exit.

This paves the way to simply wake up a blocking accept() in a portable
way.

app/src/server.c

@@ -5,6 +5,7 @@
 #include <inttypes.h>
 #include <libgen.h>
 #include <stdio.h>
+#include <SDL2/SDL_thread.h>
 #include <SDL2/SDL_timer.h>
 #include <SDL2/SDL_platform.h>
 
@@ -332,6 +333,14 @@ server_init(struct server *server) {
     *server = (struct server) SERVER_INITIALIZER;
 }
 
+static int
+run_wait_server(void *data) {
+    struct server *server = data;
+    cmd_simple_wait(server->process, NULL); // ignore exit code
+    LOGD("Server terminated");
+    return 0;
+}
+
 bool
 server_start(struct server *server, const char *serial,
              const struct server_params *params) {
@@ -358,6 +367,16 @@ server_start(struct server *server, const char *serial,
         goto error2;
     }
 
+    server->wait_server_thread =
+        SDL_CreateThread(run_wait_server, "wait-server", server);
+    if (!server->wait_server_thread) {
+        if (!cmd_terminate(server->process)) {
+            LOGW("Could not terminate server");
+        }
+        cmd_simple_wait(server->process, NULL); // ignore exit code
+        goto error2;
+    }
+
     server->tunnel_enabled = true;
 
     return true;
@@ -430,13 +449,12 @@ server_stop(struct server *server) {
         LOGW("Could not terminate server");
     }
 
-    cmd_simple_wait(server->process, NULL); // ignore exit code
-    LOGD("Server terminated");
-
     if (server->tunnel_enabled) {
         // ignore failure
         disable_tunnel(server);
     }
+
+    SDL_WaitThread(server->wait_server_thread, NULL);
 }
 
 void

app/src/server.h

@@ -3,6 +3,7 @@
 
 #include <stdbool.h>
 #include <stdint.h>
+#include <SDL2/SDL_thread.h>
 
 #include "config.h"
 #include "command.h"
@@ -12,6 +13,7 @@
 struct server {
     char *serial;
     process_t process;
+    SDL_Thread *wait_server_thread;
     socket_t server_socket; // only used if !tunnel_forward
     socket_t video_socket;
     socket_t control_socket;
@@ -24,6 +26,7 @@ struct server {
 #define SERVER_INITIALIZER { \
     .serial = NULL, \
     .process = PROCESS_NONE, \
+    .wait_server_thread = NULL, \
     .server_socket = INVALID_SOCKET, \
     .video_socket = INVALID_SOCKET, \
     .control_socket = INVALID_SOCKET, \