wayland: Rollback the round trip when reading data offers

The bug this appeared to fix turned out to be randomly occurring and has other causes, and the read pipe is already polled for readiness, so this extra overhead isn't necessary.

src/video/wayland/SDL_waylanddatamanager.c

@@ -370,15 +370,10 @@ void *Wayland_data_offer_receive(SDL_WaylandDataOffer *offer,
     } else if (pipe2(pipefd, O_CLOEXEC | O_NONBLOCK) == -1) {
         SDL_SetError("Could not read pipe");
     } else {
-        struct wl_event_queue *queue = WAYLAND_wl_display_create_queue(data_device->video_data->display);
-        WAYLAND_wl_proxy_set_queue((struct wl_proxy *)offer->offer, queue);
-
         wl_data_offer_receive(offer->offer, mime_type, pipefd[1]);
         close(pipefd[1]);
 
-        WAYLAND_wl_display_roundtrip_queue(data_device->video_data->display, queue);
-        WAYLAND_wl_proxy_set_queue((struct wl_proxy *)offer->offer, NULL);
-        WAYLAND_wl_event_queue_destroy(queue);
+        WAYLAND_wl_display_flush(data_device->video_data->display);
 
         while (read_pipe(pipefd[0], &buffer, length) > 0) {
         }
@@ -409,15 +404,10 @@ void *Wayland_primary_selection_offer_receive(SDL_WaylandPrimarySelectionOffer *
     } else if (pipe2(pipefd, O_CLOEXEC | O_NONBLOCK) == -1) {
         SDL_SetError("Could not read pipe");
     } else {
-        struct wl_event_queue *queue = WAYLAND_wl_display_create_queue(primary_selection_device->video_data->display);
-        WAYLAND_wl_proxy_set_queue((struct wl_proxy *)offer->offer, queue);
-
         zwp_primary_selection_offer_v1_receive(offer->offer, mime_type, pipefd[1]);
         close(pipefd[1]);
 
-        WAYLAND_wl_display_roundtrip_queue(primary_selection_device->video_data->display, queue);
-        WAYLAND_wl_proxy_set_queue((struct wl_proxy *)offer->offer, NULL);
-        WAYLAND_wl_event_queue_destroy(queue);
+        WAYLAND_wl_display_flush(primary_selection_device->video_data->display);
 
         while (read_pipe(pipefd[0], &buffer, length) > 0) {
         }

src/video/wayland/SDL_waylandsym.h

@@ -65,7 +65,6 @@ SDL_WAYLAND_SYM(void, wl_display_cancel_read, (struct wl_display *))
 SDL_WAYLAND_SYM(int, wl_display_get_error, (struct wl_display *))
 SDL_WAYLAND_SYM(int, wl_display_flush, (struct wl_display *))
 SDL_WAYLAND_SYM(int, wl_display_roundtrip, (struct wl_display *))
-SDL_WAYLAND_SYM(int, wl_display_roundtrip_queue, (struct wl_display *, struct wl_event_queue *))
 SDL_WAYLAND_SYM(struct wl_event_queue *, wl_display_create_queue, (struct wl_display *))
 SDL_WAYLAND_SYM(void, wl_event_queue_destroy, (struct wl_event_queue *))
 SDL_WAYLAND_SYM(void, wl_log_set_handler_client, (wl_log_func_t))