Make QWebEngine an opt-out for MinGW builds

QWebEngine does not support MinGW compilers. In order to continue
support for MinGW in swift for now, opt it out in MinGW builds.
So far this affects only the news page, which is acceptable. This
way we keep the advantages of Windows MinGW builds.

src/swiftlauncher/swiftlauncher.cpp

@@ -23,7 +23,11 @@
 #include <QProcess>
 #include <QDesktopServices>
 #include <QShortcut>
+#include <qcompilerdetection.h>
+
+#ifndef Q_CC_MINGW
 #include <QtWebEngineWidgets/QWebEngineView>
+#endif
 
 using namespace BlackGui;
 using namespace BlackCore;
@@ -123,6 +127,7 @@ void CSwiftLauncher::initStyleSheet()
 
 void CSwiftLauncher::displayLatestNews()
 {
+#ifndef Q_CC_MINGW
     CUrlList newsUrls(this->m_setup.get().swiftLatestNewsUrls());
     QUrl newUrl(newsUrls.getNextUrl());
 
@@ -135,7 +140,7 @@ void CSwiftLauncher::displayLatestNews()
     }
     view->show();
     **/
-
+#endif
 }
 
 void CSwiftLauncher::initDBusGui()

src/swiftlauncher/swiftlauncher.pro

@@ -1,6 +1,9 @@
 load(common_pre)
 
-QT       += core dbus gui svg network xml multimedia webenginewidgets
+QT       += core dbus gui svg network xml multimedia
+
+# QWebEngine is not supported for MinGW
+!win32-g++: QT += webenginewidgets
 
 greaterThan(QT_MAJOR_VERSION, 4): QT += widgets