Fix some compiler warnings

Signed-off-by: falkTX <falktx@falktx.com>

dgl/Cairo.hpp

@@ -151,7 +151,7 @@ public:
    /**
       Destructor.
     */
-    virtual ~CairoBaseWidget() {}
+    ~CairoBaseWidget() override {}
 
 protected:
    /**

dgl/NanoVG.hpp

@@ -940,7 +940,7 @@ public:
    /**
       Destructor.
     */
-    virtual ~NanoBaseWidget() {}
+    ~NanoBaseWidget() override {}
 
 protected:
    /**

dgl/OpenGL.hpp

@@ -238,11 +238,11 @@ public:
 
     // FIXME this should not be needed
     inline void loadFromMemory(const char* rdata, uint w, uint h, ImageFormat fmt = kImageFormatBGRA)
-    { loadFromMemory(rdata, Size<uint>(w, h), fmt); };
+    { loadFromMemory(rdata, Size<uint>(w, h), fmt); }
     inline void draw(const GraphicsContext& context)
-    { drawAt(context, Point<int>(0, 0)); };
+    { drawAt(context, Point<int>(0, 0)); }
     inline void drawAt(const GraphicsContext& context, int x, int y)
-    { drawAt(context, Point<int>(x, y)); };
+    { drawAt(context, Point<int>(x, y)); }
 
    /**
       Constructor using raw image data, specifying an OpenGL image format.

dgl/SubWidget.hpp

@@ -47,7 +47,7 @@ public:
    /**
       Destructor.
     */
-    virtual ~SubWidget();
+    ~SubWidget() override;
 
    /**
       Check if this widget contains the point defined by @a x and @a y.

dgl/TopLevelWidget.hpp

@@ -54,7 +54,7 @@ public:
    /**
       Destructor.
     */
-    virtual ~TopLevelWidget();
+    ~TopLevelWidget() override;
 
    /**
       Get the application associated with this top-level widget's window.

distrho/DistrhoUI.hpp

@@ -89,7 +89,7 @@ public:
    /**
       Destructor.
     */
-    virtual ~UI();
+    ~UI() override;
 
    /* --------------------------------------------------------------------------------------------------------
     * Host state */

distrho/src/DistrhoUIPrivateData.hpp

@@ -199,7 +199,7 @@ public:
             puglBackendEnter(pData->view);
     }
 
-    ~PluginWindow()
+    ~PluginWindow() override
     {
         if (pData->view != nullptr)
             puglBackendLeave(pData->view);