Fix some issues found by cppcheck

rtgui/dirbrowser.h

@@ -89,7 +89,7 @@ public:
     void updateVolumes ();
     void updateDirTree  (const Gtk::TreeModel::iterator& iter);
     void updateDirTreeRoot  ();
-    void winDirChanged ();
+    void winDirChanged () override;
 private:
     void addRoot (char letter);
 #endif

rtgui/exifpanel.cc

@@ -261,7 +261,7 @@ void ExifPanel::addDirectory (const TagDirectory* dir, Gtk::TreeModel::Children
                 Tag* t2 = (const_cast<TagDirectory*> (dir))->getTagByIndex (j);
                 const TagAttrib* currAttrib = t2->getAttrib();
 
-                if (currAttrib && ((options.lastShowAllExif) || (!options.lastShowAllExif && currAttrib->action != AC_SYSTEM))) {
+                if (currAttrib && (options.lastShowAllExif || currAttrib->action != AC_SYSTEM)) {
                     addSeparator();
                     hasContent = true;
                     break;

rtgui/filmsimulation.h

@@ -11,7 +11,7 @@
 class ClutComboBox : public MyComboBox
 {
 public:
-    ClutComboBox(const Glib::ustring &path);
+    explicit ClutComboBox(const Glib::ustring &path);
     //int fillFromDir (const Glib::ustring& path);
     int foundClutsCount() const;
     Glib::ustring getSelectedClut();
@@ -34,7 +34,7 @@ private:
         Glib::RefPtr<Gtk::TreeStore> m_model;
         ClutColumns m_columns;
         int count;
-        ClutModel(const Glib::ustring &path);
+        explicit ClutModel(const Glib::ustring &path);
         int parseDir (const Glib::ustring& path);
     };
 

rtgui/retinex.cc

@@ -11,7 +11,6 @@ using namespace rtengine::procparams;
 Retinex::Retinex () : FoldableToolPanel (this, "retinex", M ("TP_RETINEX_LABEL"), false, true), lastmedianmap (false)
 {
     CurveListener::setMulti (true);
-    std::vector<double> defaultCurve;
     std::vector<GradientMilestone> milestones;
     nextmin = 0.;
     nextmax = 0.;