Use function pointers instead of std::function

Author: adazem009

src/engine/global.h

@@ -13,9 +13,9 @@ namespace libscratchcpp
 /*!
  * \typedef BlockImpl
  *
- * BlockImpl is used to store block implementation functions as std::function in blocks.
+ * BlockImpl is a function pointer for block implementation functions.
  */
-using BlockImpl = std::function<Value(const BlockArgs &)>;
+using BlockImpl = Value (*)(const BlockArgs &);
 
 /*! Generates a random number in the given interval like the random.randint() function in Python. */
 template<typename T>

src/engine/iblocksection.h

@@ -80,7 +80,7 @@ class IBlockSection
         template<class F>
         void addBlock(const std::string &opcode, F &&f)
         {
-            m_blocks[opcode] = std::bind(f, std::placeholders::_1);
+            m_blocks[opcode] = f;
         }
 
         /*! Assigns an input ID to an input name. */