Merge remote-tracking branch 'upstream/3.4' into merge-3.4

diff --cc modules/calib3d/src/calibinit.cpp
Simple merge

diff --cc modules/core/include/opencv2/core/cvdef.h
Simple merge

diff --cc modules/imgproc/include/opencv2/imgproc.hpp
Simple merge

diff --cc modules/videoio/src/cap.cpp
index d4f6135,25e1208..521e658
--- 1/modules/videoio/src/cap.cpp
--- 2/modules/videoio/src/cap.cpp
+++ b/modules/videoio/src/cap.cpp
@@@ -469,9 -455,9 +456,10 @@@ static Ptr<IVideoCapture> IVideoCapture
      for (int i = 0; domains[i] >= 0; i++)
      {
  #if defined(HAVE_GSTREAMER)    || \
+     defined(HAVE_MSMF)         || \
      defined(HAVE_DSHOW)        || \
      defined(HAVE_INTELPERC)    || \
 +    defined(HAVE_LIBREALSENSE) || \
      defined(WINRT_VIDEO)       || \
      defined(HAVE_GPHOTO2)      || \
      (0)