Fix uninitialized variables

src/settings/backendsettingspage.cpp

@@ -68,7 +68,8 @@ BackendSettingsPage::BackendSettingsPage(SettingsDialog *dialog, QWidget *parent
   SettingsPage(dialog, parent),
   ui_(new Ui_BackendSettingsPage),
   configloaded_(false),
-  engineloaded_(false) {
+  engineloaded_(false),
+  enginetype_current_(Engine::None) {
 
   ui_->setupUi(this);
   setWindowIcon(IconLoader::Load("soundcard"));

src/settings/contextsettingspage.h

@@ -71,7 +71,7 @@ public:
 
  private:
   Ui_ContextSettingsPage *ui_;
-  QCheckBox *checkboxes_[ContextSettingsOrder::NELEMS];
+  QCheckBox *checkboxes_[ContextSettingsOrder::NELEMS]{};
 };
 
 #endif  // CONTEXTSETTINGSPAGE_H

src/settings/settingsdialog.cpp

@@ -124,6 +124,7 @@ SettingsDialog::SettingsDialog(Application *app, OSDBase *osd, QMainWindow *main
       player_(app_->player()),
       engine_(app_->player()->engine()),
       model_(app_->collection_model()->directory_model()),
+      manager_(nullptr),
       appearance_(app_->appearance()),
       ui_(new Ui_SettingsDialog),
       loading_settings_(false) {

src/settings/settingsdialog.h

@@ -120,6 +120,7 @@ class SettingsDialog : public QDialog {
 
  private:
   struct PageData {
+    PageData() : item_(nullptr), scroll_area_(nullptr), page_(nullptr) {}
     QTreeWidgetItem *item_;
     QScrollArea *scroll_area_;
     SettingsPage *page_;