The part of the GUI that this setting is relevant for does not exist in a `--disable-wallet` build. 

![wallet_prefs](https://user-images.githubusercontent.com/863730/70331435-72547300-180d-11ea-842d-82f8529ae982.png)
#if defined(HAVE_CONFIG_H)
#include <config/bitcoin-config.h>
#endif
#include <qt/optionsdialog.h>
#include <qt/forms/ui_optionsdialog.h>
#include <qt/bitcoinunits.h>
#include <qt/guiconstants.h>
#include <qt/guiutil.h>
#include <qt/optionsmodel.h>
#include <interfaces/node.h>
#include <validation.h> 
#include <netbase.h>
#include <txdb.h> 
#include <QDataWidgetMapper>
#include <QDir>
#include <QIntValidator>
#include <QLocale>
#include <QMessageBox>
#include <QSystemTrayIcon>
#include <QTimer>
OptionsDialog::OptionsDialog(QWidget *parent, bool enableWallet) :