added dummy symbol to flann to make OpenCV compile on Windows

modules/flann/include/opencv2/flann/general.h

@@ -46,6 +46,11 @@ public:
     FLANNException(const std::string& message) : std::runtime_error(message) { }
 };
 
+#if (defined WIN32 || defined _WIN32 || defined WINCE) && defined CVAPI_EXPORTS
+__declspec(dllexport)
+#endif
+void dummyfunc();
+
 }
 
 

modules/flann/src/flann.cpp

@@ -28,5 +28,4 @@
 
 #include "precomp.hpp"
 
-
-
+void cvflann::dummyfunc() {}