Codechange: make explicit that virtual functions in a con/destructor are resolved statically

This as during construction the sub class has not been initialized yet, and
during destruction the sub class has already been destroyed, so the overriding
virtual function would be accessing uninitialized data.

src/fontcache.cpp

@@ -216,7 +216,8 @@ TrueTypeFontCache::TrueTypeFontCache(FontSize fs, int pixels) : FontCache(fs), r
  */
 TrueTypeFontCache::~TrueTypeFontCache()
 {
-	this->ClearFontCache();
+	/* Virtual functions get called statically in destructors, so make it explicit to remove any confusion. */
+	this->TrueTypeFontCache::ClearFontCache();
 
 	for (auto &iter : this->font_tables) {
 		free(iter.second.second);