upgrade to qt 6 compliance

app/widget/slider/base/sliderbase.cpp

@@ -103,14 +103,26 @@ void SliderBase::changeEvent(QEvent *e)
   super::changeEvent(e);
 }
 
+bool SliderBase::GetLabelSubstitution(const QVariant &v, QString *out) const
+{
+  for (auto it=label_substitutions_.constBegin(); it!=label_substitutions_.constEnd(); it++) {
+    if (it->first == v) {
+      *out = it->second;
+      return true;
+    }
+  }
+
+  return false;
+}
+
 void SliderBase::UpdateLabel()
 {
   QString s;
 
   if (tristate_) {
     s = tr("---");
-  } else if (label_substitutions_.contains(GetValueInternal())) {
-    s = label_substitutions_.value(GetValueInternal());
+  } else if (GetLabelSubstitution(GetValueInternal(), &s)) {
+    // String will already be set, just pass through
   } else {
     s = GetFormattedValueToString();
   }

app/widget/slider/base/sliderbase.h

@@ -51,7 +51,7 @@ public:
 
   void InsertLabelSubstitution(const QVariant &value, const QString &label)
   {
-    label_substitutions_.insert(value, label);
+    label_substitutions_.append({value, label});
     UpdateLabel();
   }
 
@@ -90,6 +90,8 @@ protected:
   virtual void changeEvent(QEvent* e) override;
 
 private:
+  bool GetLabelSubstitution(const QVariant &v, QString *out) const;
+
   SliderLabel* label_;
 
   FocusableLineEdit* editor_;
@@ -103,7 +105,7 @@ private:
 
   bool format_plural_;
 
-  QMap<QVariant, QString> label_substitutions_;
+  QVector<QPair<QVariant, QString> > label_substitutions_;
 
 private slots:
   void LineEditConfirmed();

app/widget/slider/base/sliderladder.cpp

@@ -42,7 +42,7 @@ SliderLadder::SliderLadder(double drag_multiplier, int nb_outer_values, QString
   QFrame(parent, Qt::Popup)
 {
   QVBoxLayout* layout = new QVBoxLayout(this);
-  layout->setMargin(0);
+  layout->setContentsMargins(0, 0, 0, 0);
   layout->setSpacing(0);
 
   setFrameShape(QFrame::Box);