Cmake error at
opencv_contrib-master/modules/datasets/CMakeLists.txt:5 (ocv_append_source_files_cxx_compiler_options):
Unknown CMake command "ocv_append_source_files_cxx_compiler_options".

-- Configuring incomplete, errors occurred!
See also "/home/sunhong/Downloads/opencv-3.4.1/my_build_dir/CMakeFiles/CMakeOutput.log".

See also "/home/sunhong/Downloads/opencv-3.4.1/my_build_dir/CMakeFiles/CMakeError.log".

解決方法：

1.註釋掉:opencv_contrib-master/modules/datasets/CMakeLists.txt:5 (ocv_append_source_files_cxx_compiler_options):

2.

～\opencv_contrib\modules\dnn_modern\CMakeLists.txt
20行改為
ocv_download(PACKAGE "v1.0.0a3.tar.gz"

～\opencv_contrib\modules\xfeatures2d\cmake\download_boostdesc.cmake
22行改為
 ocv_download(PACKAGE

${name_${id}}

～\opencv_contrib\modules\ xfeatures2d\cmake\download_vgg.cmake
16行改為
ocv_download( PACKAGE ${name_${id}}

3. ippicv包的問題：由於網路原因