Codechange: Use std::unordered_map for storing TrueTypeFontCache's GlyphEntry.

src/spritecache.h

@@ -37,6 +37,14 @@ protected:
 	void *AllocatePtr(size_t size) override;
 };
 
+/** SpriteAllocator that allocates memory via a unique_ptr array. */
+class UniquePtrSpriteAllocator : public SpriteAllocator {
+public:
+	std::unique_ptr<uint8_t[]> data;
+protected:
+	void *AllocatePtr(size_t size) override;
+};
+
 void *GetRawSprite(SpriteID sprite, SpriteType type, SpriteAllocator *allocator = nullptr, SpriteEncoder *encoder = nullptr);
 bool SpriteExists(SpriteID sprite);