message: cmake: download tries, customizable download parameters
diff: @@ -22,6 +22,9 @@ set(OPENCV_DOWNLOAD_PATH "${OpenCV_SOURCE_DIR}/.cache" CACHE PATH "${HELP_OPENCV
  set(OPENCV_DOWNLOAD_LOG "${OpenCV_BINARY_DIR}/CMakeDownloadLog.txt")
  set(OPENCV_DOWNLOAD_WITH_CURL "${OpenCV_BINARY_DIR}/download_with_curl.sh")
  set(OPENCV_DOWNLOAD_WITH_WGET "${OpenCV_BINARY_DIR}/download_with_wget.sh")
  +set(OPENCV_DOWNLOAD_TRIES_LIST 1 CACHE STRING "List of download tries") # a list
  +set(OPENCV_DOWNLOAD_PARAMS INACTIVITY_TIMEOUT 60 TIMEOUT 600 CACHE STRING "Download parameters to be passed to file(DOWNLAOD ...)")
  +mark_as_advanced(OPENCV_DOWNLOAD_TRIES_LIST OPENCV_DOWNLOAD_PARAMS)
  # Init download cache directory and log file and helper scripts
  if(NOT EXISTS "${OPENCV_DOWNLOAD_PATH}")
  @@ -154,11 +157,17 @@ function(ocv_download)
  # Download
  if(NOT EXISTS "${CACHE_CANDIDATE}")
  ocv_download_log("#cmake_download \"${CACHE_CANDIDATE}\" \"${DL_URL}\"")
  + foreach(try ${OPENCV_DOWNLOAD_TRIES_LIST})
  + ocv_download_log("#try ${try}")
  file(DOWNLOAD "${DL_URL}" "${CACHE_CANDIDATE}"
  - INACTIVITY_TIMEOUT 60
  - TIMEOUT 600
  STATUS status
  - LOG __log)
  + LOG __log
  + ${OPENCV_DOWNLOAD_PARAMS})
  + if(status EQUAL 0)
  + break()
  + endif()
  + message(STATUS "Try ${try} failed")
  + endforeach()
  if(NOT OPENCV_SKIP_FILE_DOWNLOAD_DUMP) # workaround problem with old CMake versions: "Invalid escape sequence"
  string(LENGTH "${__log}" __log_length)
  if(__log_length LESS 65536)
  