cmake-gui: Address deprecation warnings with Qt6

Source/QtDialog/CMakeSetup.cxx

@@ -112,7 +112,10 @@ int main(int argc, char** argv)
   cmAddPluginPath();
 #endif
 
-#if QT_VERSION >= 0x050600
+// HighDpiScaling is always enabled starting with Qt6, but will still issue a
+// deprecation warning if you try to set the attribute for it
+#if (QT_VERSION >= QT_VERSION_CHECK(5, 6, 0) &&                               \
+     QT_VERSION < QT_VERSION_CHECK(6, 0, 0))
   QGuiApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
 #endif
 
@@ -132,9 +135,9 @@ int main(int argc, char** argv)
   translationsDir.cd(QString::fromLocal8Bit(".." CMAKE_DATA_DIR));
   translationsDir.cd("i18n");
   QTranslator translator;
-  QString transfile = QString("cmake_%1").arg(QLocale::system().name());
-  translator.load(transfile, translationsDir.path());
-  QApplication::installTranslator(&translator);
+  if (translator.load(QLocale(), "cmake", "_", translationsDir.path())) {
+    QApplication::installTranslator(&translator);
+  }
 
   // app setup
   QApplication::setApplicationName("CMakeSetup");

Source/QtDialog/CMakeSetupDialog.cxx

@@ -178,7 +178,11 @@ CMakeSetupDialog::CMakeSetupDialog()
                    &CMakeSetupDialog::doOutputErrorNext);
   a->setShortcut(QKeySequence(Qt::Key_F8));
   auto* s = new QShortcut(this);
+#if (QT_VERSION < QT_VERSION_CHECK(6, 0, 0))
   s->setKey(QKeySequence(Qt::CTRL + Qt::Key_Period));
+#else
+  s->setKey(QKeySequence(Qt::CTRL | Qt::Key_Period));
+#endif
   QObject::connect(s, &QShortcut::activated, this,
                    &CMakeSetupDialog::doOutputErrorNext); // in Eclipse
 

Source/QtDialog/QCMake.cxx

@@ -334,7 +334,12 @@ void QCMake::setProperties(const QCMakePropertyList& newProps)
       toremove.append(QString::fromLocal8Bit(key.c_str()));
     } else {
       prop = props[idx];
-      if (prop.Value.type() == QVariant::Bool) {
+#if (QT_VERSION < QT_VERSION_CHECK(6, 0, 0))
+      const bool isBool = prop.Value.type() == QVariant::Bool;
+#else
+      const bool isBool = prop.Value.metaType() == QMetaType::fromType<bool>();
+#endif
+      if (isBool) {
         state->SetCacheEntryValue(key, prop.Value.toBool() ? "ON" : "OFF");
       } else {
         state->SetCacheEntryValue(key,