videoio: drop obsolete backends

- VFW
- QuickTime/QtKit
- Unicap - GPL, no active support: https://github.com/unicap/unicap
- DC1394 (1st version) / CMU1394

cmake/OpenCVFindLibsVideo.cmake

@@ -2,14 +2,6 @@
 #  Detect 3rd-party video IO libraries
 # ----------------------------------------------------------------------------
 
-ocv_clear_vars(HAVE_VFW)
-if(WITH_VFW)
-  try_compile(HAVE_VFW
-    "${OpenCV_BINARY_DIR}"
-    "${OpenCV_SOURCE_DIR}/cmake/checks/vfwtest.cpp"
-    CMAKE_FLAGS "-DLINK_LIBRARIES:STRING=vfw32")
-endif(WITH_VFW)
-
 # --- GStreamer ---
 ocv_clear_vars(HAVE_GSTREAMER)
 # try to find gstreamer 1.x first if 0.10 was not requested
@@ -62,16 +54,6 @@ if(WITH_GSTREAMER AND NOT HAVE_GSTREAMER OR WITH_GSTREAMER_0_10)
   endif()
 endif(WITH_GSTREAMER AND NOT HAVE_GSTREAMER OR WITH_GSTREAMER_0_10)
 
-# --- unicap ---
-ocv_clear_vars(HAVE_UNICAP)
-if(WITH_UNICAP)
-  CHECK_MODULE(libunicap HAVE_UNICAP_  VIDEOIO)
-  CHECK_MODULE(libucil HAVE_UNICAP_UCIL  VIDEOIO)
-  if(HAVE_UNICAP_ AND HAVE_UNICAP_UCIL)
-    set(HAVE_UNICAP TRUE)
-  endif()
-endif(WITH_UNICAP)
-
 # --- PvApi ---
 ocv_clear_vars(HAVE_PVAPI)
 if(WITH_PVAPI)
@@ -286,12 +268,8 @@ endif(WITH_MSMF)
 # --- Extra HighGUI and VideoIO libs on Windows ---
 if(WIN32)
   list(APPEND HIGHGUI_LIBRARIES comctl32 gdi32 ole32 setupapi ws2_32)
-  if(HAVE_VFW)
-    list(APPEND VIDEOIO_LIBRARIES vfw32)
-  endif()
   if(MINGW64)
     list(APPEND VIDEOIO_LIBRARIES avifil32 avicap32 winmm msvfw32)
-    list(REMOVE_ITEM VIDEOIO_LIBRARIES vfw32)
   elseif(MINGW)
     list(APPEND VIDEOIO_LIBRARIES winmm)
   endif()
@@ -301,13 +279,6 @@ if(APPLE)
   if(WITH_AVFOUNDATION)
     set(HAVE_AVFOUNDATION YES)
   endif()
-  if(NOT IOS)
-    if(WITH_QUICKTIME)
-      set(HAVE_QUICKTIME YES)
-    elseif(WITH_QTKIT)
-      set(HAVE_QTKIT YES)
-    endif()
-  endif()
 endif(APPLE)
 
 # --- Intel librealsense ---