LIBSO=1 compile darknet.so library on Linux

AlexeyAB

2017-08-04 fd671a7a4a8f018e449966a8ada5020de702d742

 src/yolo_v2_class.hpp

@@ -11,9 +11,17 @@
#endif   // OPENCV

#ifdef YOLODLL_EXPORTS
#if defined(_MSC_VER)
#define YOLODLL_API __declspec(dllexport) 
#else
#define YOLODLL_API __attribute__((visibility("default")))
#endif
#else
#if defined(_MSC_VER)
#define YOLODLL_API __declspec(dllimport) 
#else
#define YOLODLL_API
#endif
#endif

struct bbox_t {