message: core: provide safe implementations of CV_XADD() only
diff: @@ -519,7 +519,11 @@ Cv64suf;
  # include <intrin.h>
  # define CV_XADD(addr, delta) (int)_InterlockedExchangeAdd((long volatile*)addr, delta)
  #else
  + #ifdef OPENCV_FORCE_UNSAFE_XADD
  CV_INLINE CV_XADD(int* addr, int delta) { int tmp = *addr; *addr += delta; return tmp; }
  + #else
  + #error "OpenCV: can't define safe CV_XADD macro for current platform (unsupported). Define CV_XADD macro through custom port header (see OPENCV_INCLUDE_PORT_FILE)"
  + #endif
  #endif
  