Add export macro for ios conversion functions

modules/imgcodecs/include/opencv2/imgcodecs/ios.h

@@ -50,8 +50,8 @@
 //! @addtogroup imgcodecs_ios
 //! @{
 
-UIImage* MatToUIImage(const cv::Mat& image);
-void UIImageToMat(const UIImage* image,
-                         cv::Mat& m, bool alphaExist = false);
+CV_EXPORTS UIImage* MatToUIImage(const cv::Mat& image);
+CV_EXPORTS void UIImageToMat(const UIImage* image,
+                             cv::Mat& m, bool alphaExist = false);
 
 //! @}

modules/imgcodecs/src/ios_conversions.mm

@@ -47,8 +47,8 @@
 #include "opencv2/core.hpp"
 #include "precomp.hpp"
 
-UIImage* MatToUIImage(const cv::Mat& image);
-void UIImageToMat(const UIImage* image, cv::Mat& m, bool alphaExist);
+CV_EXPORTS UIImage* MatToUIImage(const cv::Mat& image);
+CV_EXPORTS void UIImageToMat(const UIImage* image, cv::Mat& m, bool alphaExist);
 
 UIImage* MatToUIImage(const cv::Mat& image) {