gtk: add proper header bar for wayland.

Closes #19664.

Author: TurboGit

src/gui/gtk.c

@@ -1736,6 +1736,17 @@ static void _init_widgets(dt_gui_gtk_t *gui)
   gtk_widget_set_name(widget, "main_window");
   gui->ui->main_window = widget;
 
+#ifdef GDK_WINDOWING_WAYLAND
+  if(dt_gui_get_session_type() == DT_GUI_SESSION_WAYLAND)
+  {
+    GtkWidget *header_bar = gtk_header_bar_new();
+    gtk_header_bar_set_title(GTK_HEADER_BAR(header_bar), "darktable");
+    gtk_header_bar_set_show_close_button(GTK_HEADER_BAR(header_bar), TRUE);
+    gtk_window_set_titlebar(GTK_WINDOW(widget), header_bar);
+    gtk_widget_show(header_bar);
+  }
+#endif
+
   dt_configure_ppd_dpi(gui);
 
   gtk_window_set_default_size(GTK_WINDOW(widget),