diff --git a/unix/gtkmain.c b/unix/gtkmain.c
index eb731ea8..00db3464 100644
--- a/unix/gtkmain.c
+++ b/unix/gtkmain.c
@@ -532,6 +532,11 @@ int do_cmdline(int argc, char **argv, int do_everything, int *allow_launch,
     return err;
 }
 
+GtkWidget *make_gtk_toplevel_window(void *frontend)
+{
+    return gtk_window_new(GTK_WINDOW_TOPLEVEL);
+}
+
 extern int cfgbox(Conf *conf);
 
 int main(int argc, char **argv)
diff --git a/unix/gtkwin.c b/unix/gtkwin.c
index 3ed58b08..49db1fe5 100644
--- a/unix/gtkwin.c
+++ b/unix/gtkwin.c
@@ -4120,7 +4120,7 @@ struct gui_data *new_session_window(Conf *conf, const char *geometry_string)
             exit(1);
         }
     }
-    inst->window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
+    inst->window = make_gtk_toplevel_window(inst);
     {
         const char *winclass = conf_get_str(inst->conf, CONF_winclass);
         if (*winclass)
diff --git a/unix/unix.h b/unix/unix.h
index 3b8982c2..12ab8b1c 100644
--- a/unix/unix.h
+++ b/unix/unix.h
@@ -102,6 +102,9 @@ struct gui_data *new_session_window(Conf *conf, const char *geometry_string);
 void launch_duplicate_session(Conf *conf);
 void launch_new_session(void);
 void launch_saved_session(const char *str);
+#ifdef MAY_REFER_TO_GTK_IN_HEADERS
+GtkWidget *make_gtk_toplevel_window(void *frontend);
+#endif
 
 /* Defined in gtkcomm.c */
 void gtkcomm_setup(void);