Text: no need to have virtual destructor here.

Protected constructor and destructor is sufficient, AbstractTextRenderer
itself isn't meant to be deleted (via pointer).

src/Text/TextRenderer.h

@@ -62,16 +62,6 @@ class MAGNUM_TEXT_EXPORT AbstractTextRenderer {
          */
         static std::tuple<std::vector<Vector2>, std::vector<Vector2>, std::vector<UnsignedInt>, Rectangle> render(AbstractFont* font, const GlyphCache* cache, Float size, const std::string& text);
 
-        /**
-         * @brief Constructor
-         * @param font          Font
-         * @param cache         Glyph cache
-         * @param size          Font size
-         */
-        explicit AbstractTextRenderer(AbstractFont* font, const GlyphCache* cache, Float size);
-
-        virtual ~AbstractTextRenderer() = 0;
-
         /**
          * @brief Capacity for rendered glyphs
          *
@@ -118,6 +108,17 @@ class MAGNUM_TEXT_EXPORT AbstractTextRenderer {
          */
         void render(const std::string& text);
 
+    protected:
+        /**
+         * @brief Constructor
+         * @param font          Font
+         * @param cache         Glyph cache
+         * @param size          Font size
+         */
+        explicit AbstractTextRenderer(AbstractFont* font, const GlyphCache* cache, Float size);
+
+        ~AbstractTextRenderer();
+
     #ifndef DOXYGEN_GENERATING_OUTPUT
     protected:
     #else