[gnome-builder/wip/gtk4-port] code: use g_timeout_add()

[Christian Hergert <chergert src gnome org>]

commit 0fac83f426d644425323f49f2f514dcbe177bd60
Author: Christian Hergert <chergert redhat com>
Date:   Thu Sep 23 16:33:53 2021 -0700

    code: use g_timeout_add()
    
    The GDK API has been removed in 4.x

 src/libide/code/ide-buffer.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)
---
diff --git a/src/libide/code/ide-buffer.c b/src/libide/code/ide-buffer.c
index 6f1310ee4..26060135f 100644
--- a/src/libide/code/ide-buffer.c
+++ b/src/libide/code/ide-buffer.c
@@ -2347,9 +2347,9 @@ ide_buffer_delay_settling (IdeBuffer *self)
   g_assert (IDE_IS_BUFFER (self));
 
   g_clear_handle_id (&self->settling_source, g_source_remove);
-  self->settling_source = gdk_threads_add_timeout (SETTLING_DELAY_MSEC,
-                                                   ide_buffer_settled_cb,
-                                                   self);
+  self->settling_source = g_timeout_add (SETTLING_DELAY_MSEC,
+                                         ide_buffer_settled_cb,
+                                         self);
 }
 
 /**