catkin build opencv3_catkin failed

[heartflyinsky]

I'm trying to build this awesome work on Ubuntu 20.04, but I get stuck in the following error:

[opencv3_catkin:make] /usr/local/bin/cmake -P /home/zhanglingpeng/code/maplab_ros/build/opencv3_catkin/opencv3_src-prefix/src/opencv3_src-stamp/download-opencv3_src.cmake
[opencv3_catkin:make] -- Downloading...
[opencv3_catkin:make] dst='/home/zhanglingpeng/code/maplab_ros/build/opencv3_catkin/opencv3_src-prefix/src/3.4.2.zip'
[opencv3_catkin:make] timeout='none'
[opencv3_catkin:make] inactivity timeout='none'
[opencv3_catkin:make] -- Using src='https://github.com/opencv/opencv/archive/3.4.2.zip'
[opencv3_catkin:make] -- verifying file...
[opencv3_catkin:make] file='/home/zhanglingpeng/code/maplab_ros/build/opencv3_catkin/opencv3_src-prefix/src/3.4.2.zip'
[opencv3_catkin:make] -- Downloading... done
[opencv3_catkin:make] /usr/local/bin/cmake -P /home/zhanglingpeng/code/maplab_ros/build/opencv3_catkin/opencv3_src-prefix/src/opencv3_src-stamp/verify-opencv3_src.cmake
[opencv3_catkin:make] /usr/local/bin/cmake -P /home/zhanglingpeng/code/maplab_ros/build/opencv3_catkin/opencv3_src-prefix/src/opencv3_src-stamp/extract-opencv3_src.cmake
[opencv3_catkin:make] -- extracting...
[opencv3_catkin:make] src='/home/zhanglingpeng/code/maplab_ros/build/opencv3_catkin/opencv3_src-prefix/src/3.4.2.zip'
[opencv3_catkin:make] dst='/home/zhanglingpeng/code/maplab_ros/build/opencv3_catkin/opencv3_src'
[opencv3_catkin:make] -- extracting... [tar xfz]
[opencv3_catkin:make] -- extracting... [analysis]
[opencv3_catkin:make] -- extracting... [rename]
[opencv3_catkin:make] -- extracting... [clean up]
[opencv3_catkin:make] -- extracting... done
[opencv3_catkin:make] /usr/local/bin/cmake -E touch /home/zhanglingpeng/code/maplab_ros/build/opencv3_catkin/opencv3_src-prefix/src/opencv3_src-stamp/opencv3_src-download
[opencv3_catkin:make] [ 68%] No update step for 'opencv3_src'
[opencv3_catkin:make] cd /home/zhanglingpeng/code/maplab_ros/build/opencv3_catkin/opencv3_src && /usr/local/bin/cmake -E echo_append
[opencv3_catkin:make] cd /home/zhanglingpeng/code/maplab_ros/build/opencv3_catkin/opencv3_src && /usr/local/bin/cmake -E touch /home/zhanglingpeng/code/maplab_ros/build/opencv3_catkin/opencv3_src-prefix/src/opencv3_src-stamp/opencv3_src-update
[opencv3_catkin:make] [ 75%] Performing patch step for 'opencv3_src'
[opencv3_catkin:make] cd /home/zhanglingpeng/code/maplab_ros/build/opencv3_catkin/opencv3_src && patch -p0 < /home/zhanglingpeng/code/maplab_ros/src/maplab/dependencies/3rdparty/opencv3_catkin/fix_python_discovery.patch && patch -p1 < /home/zhanglingpeng/code/maplab_ros/src/maplab/dependencies/3rdparty/opencv3_catkin/rename_unordered_map_definition.patch
[opencv3_catkin:make] patching file cmake/OpenCVDetectPython.cmake
[opencv3_catkin:make] Hunk #1 succeeded at 186 (offset 9 lines).
[opencv3_catkin:make] patching file modules/flann/include/opencv2/flann/lsh_table.h
[opencv3_catkin:make] Hunk #1 FAILED at 39.
[opencv3_catkin:make] Hunk #2 FAILED at 132.
[opencv3_catkin:make] Hunk #3 FAILED at 197.
[opencv3_catkin:make] 3 out of 3 hunks FAILED -- saving rejects to file modules/flann/include/opencv2/flann/lsh_table.h.rej
[opencv3_catkin:make] make[2]: *** [CMakeFiles/opencv3_src.dir/build.make:117：opencv3_src-prefix/src/opencv3_src-stamp/opencv3_src-patch] 错误 1
[opencv3_catkin:make] make[2]: 离开目录“/home/zhanglingpeng/code/maplab_ros/build/opencv3_catkin”
[opencv3_catkin:make] make[1]: *** [CMakeFiles/Makefile2:350：CMakeFiles/opencv3_src.dir/all] 错误 2
[opencv3_catkin:make] make[1]: 离开目录“/home/zhanglingpeng/code/maplab_ros/build/opencv3_catkin”
[opencv3_catkin:make] make: *** [Makefile:146：all] 错误 2
Failed <<< opencv3_catkin [ 1 minute and 6.2 seconds ]
[build] Summary: 1 of 2 packages succeeded.
[build] Ignored: 121 packages were skipped or are skiplisted.
[build] Warnings: 2 packages succeeded with warnings.
[build] Abandoned: None.
[build] Failed: 1 packages failed.
[build] Runtime: 1 minute and 7.4 seconds total.
[build] Note: Workspace packages have changed, please re-source setup files to use them.

The VPN has been set and the downloading processes are OK. Just have no idea what's the problem here...
catkin config is attached.
Any suggestions are appreciated, thanks~