Qt6 port:

* Explicitly include some missing headers
* Use 'static const char*' for XPM icon
* Skip template parameters for qMakePair
* Constructor of QFileInfo is marked as 'explicit' now
* QString::fromLatin1() also accepts a QByteArray
* QDateTime::fromTime_t() is deprecated in Qt5 and has been removed in Qt6. Use QDateTime::fromSecsSinceEpoch()
* QDateTime::toTime_t() is deprecated in Qt5 and has been removed in Qt6. Use QDateTime::toSecsSinceEpoch()
* QApplication::globalStrut() is deprecated. Don't use it any more.
* QWidget::isTopLevel() is deprecated, use QWidget::isWindow()

src/Gui/CommandView.cpp

@@ -2852,7 +2852,7 @@ void StdBoxSelection::activated(int iMsg)
 // Std_BoxElementSelection
 //===========================================================================
 /* XPM */
-static char * cursor_box_element_select[] = {
+static const char * cursor_box_element_select[] = {
 "32 32 6 1",
 " 	c None",
 ".	c #FFFFFF",