Use static linking instead of dynamic linking

include/core/Transform2D.hpp

@@ -1,16 +1,6 @@
 #ifndef TRANSFORM2D_H
 #define TRANSFORM2D_H
 
-#if defined(_WIN32)
-#  ifdef _GD_CPP_CORE_API_IMPL
-#    define GD_CPP_CORE_API __declspec(dllexport)
-#  else
-#    define GD_CPP_CORE_API __declspec(dllimport)
-#  endif
-#else
-#  define GD_CPP_CORE_API
-#endif
-
 #include "Vector2.hpp"
 
 
@@ -20,7 +10,7 @@ typedef Vector2 Size2;
 
 class Rect2;
 
-struct GD_CPP_CORE_API Transform2D {
+struct Transform2D {
 	// Warning #1: basis of Transform2D is stored differently from Basis. In terms of elements array, the basis matrix looks like "on paper":
 	// M = (elements[0][0] elements[1][0])
 	//     (elements[0][1] elements[1][1])