diff --git a/src/defines.pri b/src/defines.pri
index ef1d35f6f..d82dfc48a 100644
--- a/src/defines.pri
+++ b/src/defines.pri
@@ -66,9 +66,12 @@ equals(d_disable_dbus, "true") { DEFINES *= DISABLE_DBUS }
 
     DEFINES *= USE_DATADIR=\\\"""$$data_folder/"\\\""
 
-    #Git revision
+    # Git revision
     rev = $$system(cd ../ && sh $$PWD/../scripts/getrevision.sh)
     !equals(rev, ""): DEFINES *= GIT_REVISION=\\\"""$$rev"\\\""
+
+    # Define QZ_WS_X11 even with Qt5
+    DEFINES *= QZ_WS_X11
 }
 
 isEmpty(QMAKE_LRELEASE) {
diff --git a/src/lib/3rdparty/processinfo.cpp b/src/lib/3rdparty/processinfo.cpp
index 452367314..add045962 100644
--- a/src/lib/3rdparty/processinfo.cpp
+++ b/src/lib/3rdparty/processinfo.cpp
@@ -17,7 +17,7 @@
 * ============================================================ */
 #include "processinfo.h"
 
-#ifdef Q_WS_X11
+#ifdef QZ_WS_X11
 #include <unistd.h>
 #include <dirent.h>
 #include <sys/types.h>
@@ -37,7 +37,7 @@ ProcessInfo::ProcessInfo(const QString &name)
 
 bool ProcessInfo::isRunning() const
 {
-#ifdef Q_WS_X11
+#ifdef QZ_WS_X11
     pid_t pid = GetPIDbyName(qPrintable(m_name));
     // -1 = process not found
     // -2 = /proc fs access error
@@ -47,7 +47,7 @@ bool ProcessInfo::isRunning() const
 #endif
 }
 
-#ifdef Q_WS_X11
+#ifdef QZ_WS_X11
 bool ProcessInfo::IsNumeric(const char* ccharptr_CharacterList) const
 {
     for (; *ccharptr_CharacterList; ccharptr_CharacterList++) {
diff --git a/src/lib/3rdparty/processinfo.h b/src/lib/3rdparty/processinfo.h
index 6becda2d5..2f1843fbe 100644
--- a/src/lib/3rdparty/processinfo.h
+++ b/src/lib/3rdparty/processinfo.h
@@ -35,7 +35,7 @@ public:
     bool isRunning() const;
 
 private:
-#ifdef Q_WS_X11
+#ifdef QZ_WS_X11
     bool IsNumeric(const char* ccharptr_CharacterList) const;
 
     pid_t GetPIDbyName(const char* cchrptr_ProcessName) const;
diff --git a/src/lib/3rdparty/qtsingleapplication.cpp b/src/lib/3rdparty/qtsingleapplication.cpp
index 6aa38cd94..4e26c451f 100644
--- a/src/lib/3rdparty/qtsingleapplication.cpp
+++ b/src/lib/3rdparty/qtsingleapplication.cpp
@@ -179,53 +179,6 @@ QtSingleApplication::QtSingleApplication(const QString &appId, int &argc, char**
     sysInit(appId);
 }
 
-#if defined(Q_WS_X11)
-/*!
-  Special constructor for X11, ref. the documentation of
-  QApplication's corresponding constructor. The application identifier
-  will be QCoreApplication::applicationFilePath(). \a dpy, \a visual,
-  and \a cmap are passed on to the QApplication constructor.
-*/
-QtSingleApplication::QtSingleApplication(Display* dpy, Qt::HANDLE visual, Qt::HANDLE cmap)
-    : QApplication(dpy, visual, cmap)
-    , peer(0)
-    , actWin(0)
-{
-    sysInit();
-}
-
-/*!
-  Special constructor for X11, ref. the documentation of
-  QApplication's corresponding constructor. The application identifier
-  will be QCoreApplication::applicationFilePath(). \a dpy, \a argc, \a
-  argv, \a visual, and \a cmap are passed on to the QApplication
-  constructor.
-*/
-QtSingleApplication::QtSingleApplication(Display* dpy, int &argc, char** argv, Qt::HANDLE visual, Qt::HANDLE cmap)
-    : QApplication(dpy, argc, argv, visual, cmap)
-    , peer(0)
-    , actWin(0)
-{
-    sysInit();
-}
-
-/*!
-  Special constructor for X11, ref. the documentation of
-  QApplication's corresponding constructor. The application identifier
-  will be \a appId. \a dpy, \a argc, \a
-  argv, \a visual, and \a cmap are passed on to the QApplication
-  constructor.
-*/
-QtSingleApplication::QtSingleApplication(Display* dpy, const QString &appId, int argc, char** argv, Qt::HANDLE visual, Qt::HANDLE cmap)
-    : QApplication(dpy, argc, argv, visual, cmap)
-    , peer(0)
-    , actWin(0)
-{
-    sysInit(appId);
-}
-#endif
-
-
 /*!
     Returns true if another instance of this application is running;
     otherwise false.
diff --git a/src/lib/3rdparty/qtsingleapplication.h b/src/lib/3rdparty/qtsingleapplication.h
index 0532656c1..b7936a4fc 100644
--- a/src/lib/3rdparty/qtsingleapplication.h
+++ b/src/lib/3rdparty/qtsingleapplication.h
@@ -72,11 +72,6 @@ class QT_QTSINGLEAPPLICATION_EXPORT QtSingleApplication : public QApplication
 public:
     QtSingleApplication(int &argc, char** argv, bool GUIenabled = true);
     QtSingleApplication(const QString &id, int &argc, char** argv);
-#if defined(Q_WS_X11)
-    QtSingleApplication(Display* dpy, Qt::HANDLE visual = 0, Qt::HANDLE colormap = 0);
-    QtSingleApplication(Display* dpy, int &argc, char** argv, Qt::HANDLE visual = 0, Qt::HANDLE cmap = 0);
-    QtSingleApplication(Display* dpy, const QString &appId, int argc, char** argv, Qt::HANDLE visual = 0, Qt::HANDLE colormap = 0);
-#endif
 
     bool isRunning();
     void setAppId(const QString &id);
diff --git a/src/lib/app/mainapplication.cpp b/src/lib/app/mainapplication.cpp
index 2e01f1393..015b61524 100644
--- a/src/lib/app/mainapplication.cpp
+++ b/src/lib/app/mainapplication.cpp
@@ -96,7 +96,7 @@ MainApplication::MainApplication(int &argc, char** argv)
     , m_databaseConnected(false)
     , m_registerQAppAssociation(0)
 {
-#if defined(Q_WS_X11) && !defined(NO_SYSTEM_DATAPATH)
+#if defined(QZ_WS_X11) && !defined(NO_SYSTEM_DATAPATH)
     DATADIR = USE_DATADIR;
 #else
     DATADIR = qApp->applicationDirPath() + "/";
@@ -309,7 +309,7 @@ void MainApplication::loadSettings()
     cssFile.open(QFile::ReadOnly);
     QString css = cssFile.readAll();
     cssFile.close();
-#ifdef Q_WS_X11
+#ifdef QZ_WS_X11
     if (QFile(m_activeThemePath + "linux.css").exists()) {
         cssFile.setFileName(m_activeThemePath + "linux.css");
         cssFile.open(QFile::ReadOnly);
diff --git a/src/lib/app/qupzilla.cpp b/src/lib/app/qupzilla.cpp
index e505a1a32..3e58ec50d 100644
--- a/src/lib/app/qupzilla.cpp
+++ b/src/lib/app/qupzilla.cpp
@@ -81,15 +81,14 @@
 #include <QWebHistory>
 #include <QMessageBox>
 
-#ifdef Q_WS_X11
+#if QT_VERSION < 0x050000
+#include "qwebkitversion.h"
+#ifdef QZ_WS_X11
 #include <QX11Info>
 #include <X11/Xlib.h>
 #include <X11/Xatom.h>
-#endif
-
-#if QT_VERSION < 0x050000
-#include "qwebkitversion.h"
-#endif
+#endif // QZ_WS_X11
+#endif // QT_VERSION
 
 const QString QupZilla::VERSION = "1.3.5";
 const QString QupZilla::BUILDTIME =  __DATE__" "__TIME__;
@@ -126,7 +125,7 @@ QupZilla::QupZilla(Qz::BrowserWindow type, QUrl startUrl)
 
     m_isStarting = true;
 
-#ifndef Q_WS_X11
+#ifndef QZ_WS_X11
     setUpdatesEnabled(false);
 #endif
 
@@ -139,7 +138,7 @@ QupZilla::QupZilla(Qz::BrowserWindow type, QUrl startUrl)
 
 void QupZilla::postLaunch()
 {
-#ifdef Q_WS_X11
+#ifdef QZ_WS_X11
     setUpdatesEnabled(false);
 #endif
 
@@ -314,7 +313,7 @@ void QupZilla::setupMenu()
     m_actionQuit = new QAction(QIcon::fromTheme("application-exit"), tr("Quit"), 0);
     m_actionQuit->setMenuRole(QAction::QuitRole);
     QKeySequence quitSequence = QKeySequence(QKeySequence::Quit);
-#ifdef Q_WS_X11
+#ifdef QZ_WS_X11
     // QKeySequence::Quit returns a non-empty sequence on X11 only when running Gnome or Kde
     if (quitSequence.isEmpty()) {
         quitSequence = QKeySequence(Qt::CTRL + Qt::Key_Q);
@@ -364,7 +363,7 @@ void QupZilla::setupMenu()
     m_menuEdit->addAction(QIcon::fromTheme("edit-select-all"), tr("Select &All"), this, SLOT(editSelectAll()))->setShortcut(QKeySequence("Ctrl+A"));
     m_menuEdit->addAction(QIcon::fromTheme("edit-find"), tr("&Find"), this, SLOT(searchOnPage()))->setShortcut(QKeySequence("Ctrl+F"));
     m_menuEdit->addSeparator();
-#ifdef Q_WS_X11
+#ifdef QZ_WS_X11
     m_menuEdit->addAction(m_actionPreferences);
 #endif
     connect(m_menuEdit, SIGNAL(aboutToShow()), this, SLOT(aboutToShowEditMenu()));
@@ -485,7 +484,7 @@ void QupZilla::setupMenu()
     connect(m_actionPrivateBrowsing, SIGNAL(triggered(bool)), mApp, SLOT(startPrivateBrowsing()));
     m_menuTools->addAction(m_actionPrivateBrowsing);
     m_menuTools->addSeparator();
-#if !defined(Q_WS_X11) && !defined(Q_OS_MAC)
+#if !defined(QZ_WS_X11) && !defined(Q_OS_MAC)
     m_menuTools->addAction(m_actionPreferences);
 #endif
 
@@ -633,7 +632,7 @@ void QupZilla::loadSettings()
         return;
     }
     //Opacity
-#ifdef Q_WS_X11
+#ifdef QZ_WS_X11
     setAttribute(Qt::WA_TranslucentBackground);
     setAttribute(Qt::WA_NoSystemBackground, false);
     QPalette pal = palette();
@@ -1887,7 +1886,7 @@ bool QupZilla::quitApp()
 
 QByteArray QupZilla::saveState(int version) const
 {
-#ifdef Q_WS_X11
+#if defined(QZ_WS_X11) && QT_VERSION < 0x050000
     QByteArray data;
     QDataStream stream(&data, QIODevice::WriteOnly);
 
@@ -1902,7 +1901,7 @@ QByteArray QupZilla::saveState(int version) const
 
 bool QupZilla::restoreState(const QByteArray &state, int version)
 {
-#ifdef Q_WS_X11
+#if defined(QZ_WS_X11) && QT_VERSION < 0x050000
     QByteArray windowState;
     int desktopId = -1;
 
@@ -1918,7 +1917,7 @@ bool QupZilla::restoreState(const QByteArray &state, int version)
 #endif
 }
 
-#ifdef Q_WS_X11
+#if defined(QZ_WS_X11) && QT_VERSION < 0x050000
 int QupZilla::getCurrentVirtualDesktop() const
 {
     Display* display = QX11Info::display();
diff --git a/src/lib/app/qupzilla.h b/src/lib/app/qupzilla.h
index b997a92d8..3a96c750e 100644
--- a/src/lib/app/qupzilla.h
+++ b/src/lib/app/qupzilla.h
@@ -210,7 +210,7 @@ private:
     bool eventFilter(QObject* object, QEvent* event);
 #endif
 
-#ifdef Q_WS_X11
+#if defined(QZ_WS_X11) && QT_VERSION < 0x050000
     int getCurrentVirtualDesktop() const;
     void moveToVirtualDesktop(int desktopId);
 #endif
diff --git a/src/lib/app/qz_namespace.h b/src/lib/app/qz_namespace.h
index 10acecec3..42f36634d 100644
--- a/src/lib/app/qz_namespace.h
+++ b/src/lib/app/qz_namespace.h
@@ -90,7 +90,7 @@ Q_DECLARE_OPERATORS_FOR_FLAGS(Qz::NewTabPositionFlags)
 
 #ifdef Q_OS_WIN
 #define DEFAULT_THEME_NAME "windows"
-#elif defined(Q_WS_X11)
+#elif defined(QZ_WS_X11)
 #define DEFAULT_THEME_NAME "linux"
 #elif defined(Q_OS_MAC)
 #define DEFAULT_THEME_NAME "mac"
diff --git a/src/lib/desktopnotifications/desktopnotificationsfactory.cpp b/src/lib/desktopnotifications/desktopnotificationsfactory.cpp
index 9cff4a01e..0bc620b76 100644
--- a/src/lib/desktopnotifications/desktopnotificationsfactory.cpp
+++ b/src/lib/desktopnotifications/desktopnotificationsfactory.cpp
@@ -23,7 +23,7 @@
 #include <QFile>
 #include <QDir>
 
-#if defined(Q_WS_X11) && !defined(DISABLE_DBUS)
+#if defined(QZ_WS_X11) && !defined(DISABLE_DBUS)
 #include <QDBusInterface>
 #endif
 
@@ -40,7 +40,7 @@ void DesktopNotificationsFactory::loadSettings()
     settings.beginGroup("Notifications");
     m_enabled = settings.value("Enabled", true).toBool();
     m_timeout = settings.value("Timeout", 6000).toInt();
-#ifdef Q_WS_X11
+#ifdef QZ_WS_X11
     m_notifType = settings.value("UseNativeDesktop", true).toBool() ? DesktopNative : PopupWidget;
 #else
     m_notifType = PopupWidget;
@@ -51,7 +51,7 @@ void DesktopNotificationsFactory::loadSettings()
 
 bool DesktopNotificationsFactory::supportsNativeNotifications() const
 {
-#if defined(Q_WS_X11) && !defined(DISABLE_DBUS)
+#if defined(QZ_WS_X11) && !defined(DISABLE_DBUS)
     return true;
 #else
     return false;
@@ -77,7 +77,7 @@ void DesktopNotificationsFactory::showNotification(const QPixmap &icon, const QS
         m_desktopNotif.data()->show();
         break;
     case DesktopNative:
-#if defined(Q_WS_X11) && !defined(DISABLE_DBUS)
+#if defined(QZ_WS_X11) && !defined(DISABLE_DBUS)
         QFile tmp(mApp->tempPath() + "/qupzilla_notif.png");
         tmp.open(QFile::WriteOnly);
         icon.save(tmp.fileName());
@@ -104,7 +104,7 @@ void DesktopNotificationsFactory::showNotification(const QPixmap &icon, const QS
 
 void DesktopNotificationsFactory::nativeNotificationPreview()
 {
-#if defined(Q_WS_X11) && !defined(DISABLE_DBUS)
+#if defined(QZ_WS_X11) && !defined(DISABLE_DBUS)
     QFile tmp(mApp->tempPath() + "/qupzilla_notif.png");
     tmp.open(QFile::WriteOnly);
     QPixmap(":icons/preferences/dialog-question.png").save(tmp.fileName());
diff --git a/src/lib/network/schemehandlers/qupzillaschemehandler.cpp b/src/lib/network/schemehandlers/qupzillaschemehandler.cpp
index eb5b0c4f9..81d948621 100644
--- a/src/lib/network/schemehandlers/qupzillaschemehandler.cpp
+++ b/src/lib/network/schemehandlers/qupzillaschemehandler.cpp
@@ -393,7 +393,7 @@ QString QupZillaSchemeReply::configPage()
 #if defined(Q_OS_WIN) && defined(W7API)
         w7APIEnabled = tr("<b>Enabled</b>");
 #endif
-#if defined(Q_WS_X11) && defined(KDE)
+#if defined(QZ_WS_X11) && defined(KDE)
         KDEIntegration = tr("<b>Enabled</b>");
 #endif
 #ifdef PORTABLE_BUILD
diff --git a/src/lib/plugins/plugins.cpp b/src/lib/plugins/plugins.cpp
index efb6365eb..c751df9ce 100644
--- a/src/lib/plugins/plugins.cpp
+++ b/src/lib/plugins/plugins.cpp
@@ -163,7 +163,7 @@ void Plugins::loadAvailablePlugins()
 
     QStringList dirs;
     dirs << mApp->DATADIR + "plugins/"
-#ifdef Q_WS_X11
+#ifdef QZ_WS_X11
 #ifdef USE_LIBPATH
          << USE_LIBPATH "qupzilla/"
 #else
diff --git a/src/lib/preferences/preferences.cpp b/src/lib/preferences/preferences.cpp
index cd8824fc1..90c146997 100644
--- a/src/lib/preferences/preferences.cpp
+++ b/src/lib/preferences/preferences.cpp
@@ -364,7 +364,7 @@ Preferences::Preferences(QupZilla* mainClass, QWidget* parent)
     DesktopNotificationsFactory::Type notifyType;
     settings.beginGroup("Notifications");
     ui->notificationTimeout->setValue(settings.value("Timeout", 6000).toInt() / 1000);
-#ifdef Q_WS_X11
+#ifdef QZ_WS_X11
     notifyType = settings.value("UseNativeDesktop", true).toBool() ? DesktopNotificationsFactory::DesktopNative : DesktopNotificationsFactory::PopupWidget;
 #else
     notifyType = DesktopNotificationsFactory::PopupWidget;
diff --git a/src/lib/rss/rssnotification.cpp b/src/lib/rss/rssnotification.cpp
index 0bd65f8b7..e7b9f7974 100644
--- a/src/lib/rss/rssnotification.cpp
+++ b/src/lib/rss/rssnotification.cpp
@@ -61,7 +61,7 @@ RSSNotification::RSSNotification(const QString &title, const QUrl &url, WebView*
               << RssApp("Netvibes", "http://www.netvibes.com/subscribe.php?url=", QIcon(":/icons/sites/netvibes.png"))
               << RssApp("Yahoo!", "http://add.my.yahoo.com/rss?url=", QIcon(":/icons/sites/yahoo.png"));
 
-#ifdef Q_WS_X11
+#ifdef QZ_WS_X11
     // TODO: Not really clever solution.
     // It should look in PATH
     if (QFile("/usr/bin/akregator").exists()) {
diff --git a/src/lib/tools/iconprovider.cpp b/src/lib/tools/iconprovider.cpp
index 41e9f65da..ef1e59069 100644
--- a/src/lib/tools/iconprovider.cpp
+++ b/src/lib/tools/iconprovider.cpp
@@ -158,7 +158,7 @@ QIcon IconProvider::standardIcon(QStyle::StandardPixmap icon)
     case QStyle::SP_MessageBoxWarning:
         return QIcon::fromTheme("dialog-warning", mApp->style()->standardIcon(QStyle::SP_MessageBoxWarning));
 
-#ifdef Q_WS_X11
+#ifdef QZ_WS_X11
     default:
         return mApp->style()->standardIcon(icon);
 #else
diff --git a/src/main/main.cpp b/src/main/main.cpp
index 69f539d97..0f2f595c3 100644
--- a/src/main/main.cpp
+++ b/src/main/main.cpp
@@ -117,7 +117,7 @@ int main(int argc, char* argv[])
 {
     QT_REQUIRE_VERSION(argc, argv, "4.7.0");
 
-#ifdef Q_WS_X11
+#if defined(QZ_WS_X11) && QT_VERSION < 0x050000
     QApplication::setGraphicsSystem("raster"); // Better overall performance on X11
 #endif