Included c-headers for better 2.4 compatibility

modules/core/include/opencv2/core/cvdef.h

@@ -73,6 +73,10 @@
 #  define CV_ENABLE_UNROLLED 1
 #endif
 
+#ifdef __OPENCV_BUILD
+#  define DISABLE_OPENCV_24_COMPATIBILITY
+#endif
+
 #if (defined WIN32 || defined _WIN32 || defined WINCE || defined __CYGWIN__) && defined CVAPI_EXPORTS
 #  define CV_EXPORTS __declspec(dllexport)
 #elif defined __GNUC__ && __GNUC__ >= 4

modules/core/include/opencv2/core/cvstd.hpp

@@ -303,7 +303,10 @@ struct Ptr
     @note It is often easier to use makePtr instead.
      */
     template<typename Y>
-    explicit Ptr(Y* p);
+#ifdef DISABLE_OPENCV_24_COMPATIBILITY
+    explicit
+#endif
+    Ptr(Y* p);
 
     /** @overload
     @param d Deleter to use for the owned pointer.

modules/core/include/opencv2/core/utility.hpp

@@ -746,4 +746,8 @@ template<> inline std::string CommandLineParser::get<std::string>(const String&
 
 } //namespace cv
 
+#ifndef DISABLE_OPENCV_24_COMPATIBILITY
+#include "opencv2/core/core_c.h"
+#endif
+
 #endif //__OPENCV_CORE_UTILITY_H__