Add a reallocate_fn() to DefConfiguration implemented around new/delete

include/wrenpp/def_configuration.hpp

@@ -29,5 +29,6 @@ namespace wren {
 	public:
 		static void write_fn (VM*, const char* text);
 		static void error_fn (VM*, ErrorType, const char* module, int line, const char* msg);
+		static void* reallocate_fn(void* ptr, std::size_t size);
 	};
 } //namespace wren

src/def_configuration.cpp

@@ -17,6 +17,7 @@
 
 #include "wrenpp/def_configuration.hpp"
 #include <iostream>
+#include <algorithm>
 
 namespace wren {
 	void DefConfiguration::write_fn (VM*, const char* text) {
@@ -26,4 +27,26 @@ namespace wren {
 	void DefConfiguration::error_fn (VM*, ErrorType type, const char* module, int line, const char* message) {
 		std::cerr << "Wren error: " << message << " in " << module << ':' << line << '\n';
 	}
+
+	void* DefConfiguration::reallocate_fn (void* ptr, std::size_t size) {
+		if (ptr and size) {
+			//reallocate
+			char* const old_mem = static_cast<char*>(ptr);
+			char* const new_mem = new char[size];
+			std::copy(old_mem, old_mem + size, new_mem);
+			delete[] old_mem;
+			return new_mem;
+		}
+		else if (ptr and not size) {
+			//free
+			char* const old_mem = static_cast<char*>(ptr);
+			delete[] old_mem;
+		}
+		else if (not ptr and size) {
+			//allocate
+			char* const new_mem = new char[size];
+			return new_mem;
+		}
+		return nullptr;
+	}
 } //namespace wren