message: Fix missing return type for unsafe CV_XADD function
diff: @@ -554,7 +554,7 @@ Cv64suf;
  # 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; }
  + CV_INLINE int 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
  