message: cmake: emit warnings about unsupported options if turned ON only
diff: @@ -605,7 +605,9 @@ macro(OCV_OPTION variable description value)
  option(${variable} "${description}" ${__value})
  endif()
  else()
  - if(DEFINED ${variable} AND NOT OPENCV_HIDE_WARNING_UNSUPPORTED_OPTION)
  + if(DEFINED ${variable} AND "${${variable}}" # emit warnings about turned ON options only.
  + AND NOT (OPENCV_HIDE_WARNING_UNSUPPORTED_OPTION OR "$ENV{OPENCV_HIDE_WARNING_UNSUPPORTED_OPTION}")
  + )
  message(WARNING "Unexpected option: ${variable} (=${${variable}})\nCondition: IF (${__condition})")
  endif()
  if(OPENCV_UNSET_UNSUPPORTED_OPTION)
  