don't use constructors for C API structures

modules/core/include/opencv2/core/core_c.h

@@ -3064,7 +3064,7 @@ template<typename _Tp> inline void Seq<_Tp>::copyTo(std::vector<_Tp>& vec, const
     size_t len = !seq ? 0 : range == Range::all() ? seq->total : range.end - range.start;
     vec.resize(len);
     if( seq && len )
-        cvCvtSeqToArray(seq, &vec[0], range);
+        cvCvtSeqToArray(seq, &vec[0], cvSlice(range));
 }
 
 template<typename _Tp> inline Seq<_Tp>::operator std::vector<_Tp>() const

modules/core/include/opencv2/core/types_c.h

@@ -44,7 +44,9 @@
 #ifndef OPENCV_CORE_TYPES_H
 #define OPENCV_CORE_TYPES_H
 
+#if !defined(__OPENCV_BUILD) && !defined(CV__DISABLE_C_API_CTORS)
 #define CV__ENABLE_C_API_CTORS // enable C API ctors (must be removed)
+#endif
 
 //#define CV__VALIDATE_UNUNITIALIZED_VARS 1  // C++11 & GCC only