Fix build with GLib < 2.32

Second part of #1047.

src/document.c

@@ -3180,17 +3180,16 @@ static gboolean on_sci_key(GtkWidget *widget, GdkEventKey *event, gpointer data)
 }
 
 /* g_signal_handlers_disconnect_by_data is a macro that cannot be used as GCallback */
-static gint nonmacro_g_signal_handlers_disconnect_by_data(gpointer instance, gpointer data)
+static void on_bar_unrealize(GtkWidget *bar, ScintillaObject *sci)
 {
-	return g_signal_handlers_disconnect_by_data(instance, data);
+	g_signal_handlers_disconnect_by_func(sci, on_sci_key, bar);
 }
 
 static void enable_key_intercept(GeanyDocument *doc, GtkWidget *bar)
 {
-	g_signal_connect(doc->editor->sci, "key-press-event",   G_CALLBACK(on_sci_key), bar);
+	g_signal_connect(doc->editor->sci, "key-press-event", G_CALLBACK(on_sci_key), bar);
 	/* make the signal disconnect automatically */
-	g_signal_connect_swapped(bar, "unrealize",
-			G_CALLBACK(nonmacro_g_signal_handlers_disconnect_by_data), doc->editor->sci);
+	g_signal_connect(bar, "unrealize", G_CALLBACK(on_bar_unrealize), doc->editor->sci);
 }
 
 static void monitor_reload_file(GeanyDocument *doc)