How to solve the error when I test the "Hello AI World" example of Nvidia

The example is here: https://github.com/dusty-nv/jetson-inference/blob/python/docs/building-repo-2.md

I did it strictly according to the steps of the tutorial,but at this step:
Compiling the Project
Make sure you are still in the jetson-inference/build directory, created above in step #3.
Then run make followed by sudo make install to build the libraries, Python extension bindings, and code samples:
cd jetson-inference/build # omit if pwd is already /build from above make
$ sudo make install

when I did the command “make”,two errors occured:

hld@hld-desktop:~/jetson-inference/build$ make

Note: this project uses git submodules in the source tree.
if you haven’t already, run the following command from
the project’s root directory:

       git submodule update --init

– using patched FindCUDA.cmake
– CUDA version: 10.0
– CUDA 10 detected, enabling SM_72
– system arch: aarch64
– output path: /home/hld/jetson-inference/build/aarch64
– Copying /home/hld/jetson-inference/c/detectNet.h
– Copying /home/hld/jetson-inference/c/homographyNet.h
– Copying /home/hld/jetson-inference/c/imageNet.h
– Copying /home/hld/jetson-inference/c/segNet.h
– Copying /home/hld/jetson-inference/c/superResNet.h
– Copying /home/hld/jetson-inference/c/tensorNet.h
– Copying /home/hld/jetson-inference/c/imageNet.cuh
– Copying /home/hld/jetson-inference/calibration/randInt8Calibrator.h
– Could NOT find Doxygen (missing: DOXYGEN_EXECUTABLE)
– found Qt5Widgets version: 5.9.5
– found Qt5Widgets defines: -DQT_WIDGETS_LIB;-DQT_GUI_LIB;-DQT_CORE_LIB
– found Qt5Widgets library: Qt5::Widgets
– found Qt5Widgets include: /usr/include/aarch64-linux-gnu/qt5/;/usr/include/aarch64-linux-gnu/qt5/QtWidgets;/usr/include/aarch64-linux-gnu/qt5/QtGui;/usr/include/aarch64-linux-gnu/qt5/QtCore;/usr/lib/aarch64-linux-gnu/qt5//mkspecs/linux-g++
– camera-capture: building as submodule, /home/hld/jetson-inference/tools
– jetson-utils: building as submodule, /home/hld/jetson-inference
– Copying /home/hld/jetson-inference/utils/XML.h
– Copying /home/hld/jetson-inference/utils/commandLine.h
– Copying /home/hld/jetson-inference/utils/filesystem.h
– Copying /home/hld/jetson-inference/utils/mat33.h
– Copying /home/hld/jetson-inference/utils/pi.h
– Copying /home/hld/jetson-inference/utils/rand.h
– Copying /home/hld/jetson-inference/utils/timespec.h
– Copying /home/hld/jetson-inference/utils/camera/gstCamera.h
– Copying /home/hld/jetson-inference/utils/camera/v4l2Camera.h
– Copying /home/hld/jetson-inference/utils/codec/gstDecoder.h
– Copying /home/hld/jetson-inference/utils/codec/gstEncoder.h
– Copying /home/hld/jetson-inference/utils/codec/gstUtility.h
– Copying /home/hld/jetson-inference/utils/cuda/cudaFont.h
– Copying /home/hld/jetson-inference/utils/cuda/cudaMappedMemory.h
– Copying /home/hld/jetson-inference/utils/cuda/cudaNormalize.h
– Copying /home/hld/jetson-inference/utils/cuda/cudaOverlay.h
– Copying /home/hld/jetson-inference/utils/cuda/cudaRGB.h
– Copying /home/hld/jetson-inference/utils/cuda/cudaResize.h
– Copying /home/hld/jetson-inference/utils/cuda/cudaUtility.h
– Copying /home/hld/jetson-inference/utils/cuda/cudaWarp.h
– Copying /home/hld/jetson-inference/utils/cuda/cudaYUV.h
– Copying /home/hld/jetson-inference/utils/display/glDisplay.h
– Copying /home/hld/jetson-inference/utils/display/glTexture.h
– Copying /home/hld/jetson-inference/utils/display/glUtility.h
– Copying /home/hld/jetson-inference/utils/image/imageIO.h
– Copying /home/hld/jetson-inference/utils/image/loadImage.h
– Copying /home/hld/jetson-inference/utils/input/devInput.h
– Copying /home/hld/jetson-inference/utils/input/devJoystick.h
– Copying /home/hld/jetson-inference/utils/input/devKeyboard.h
– Copying /home/hld/jetson-inference/utils/network/Endian.h
– Copying /home/hld/jetson-inference/utils/network/IPv4.h
– Copying /home/hld/jetson-inference/utils/network/NetworkAdapter.h
– Copying /home/hld/jetson-inference/utils/network/Socket.h
– Copying /home/hld/jetson-inference/utils/threads/Event.h
– Copying /home/hld/jetson-inference/utils/threads/Mutex.h
– Copying /home/hld/jetson-inference/utils/threads/Process.h
– Copying /home/hld/jetson-inference/utils/threads/Thread.h
– trying to build Python bindings for Python versions: 2.7;3.6;3.7
– detecting Python 2.7…
– found Python version: 2.7 (2.7.15+)
– found Python include: /usr/include/python2.7
– found Python library: /usr/lib/aarch64-linux-gnu/libpython2.7.so
– CMake module path: /home/hld/jetson-inference/utils/cuda;/home/hld/jetson-inference/utils/python/bindings
– NumPy ver. 1.13.3 found (include: /usr/lib/python2.7/dist-packages/numpy/core/include)
– found NumPy version: 1.13.3
– found NumPy include: /usr/lib/python2.7/dist-packages/numpy/core/include
– detecting Python 3.6…
– found Python version: 3.6 (3.6.8)
– found Python include: /usr/include/python3.6m
– found Python library: /usr/lib/aarch64-linux-gnu/libpython3.6m.so
– CMake module path: /home/hld/jetson-inference/utils/cuda;/home/hld/jetson-inference/utils/python/bindings
– NumPy ver. 1.17.4 found (include: /usr/local/lib/python3.6/dist-packages/numpy/core/include)
– found NumPy version: 1.17.4
– found NumPy include: /usr/local/lib/python3.6/dist-packages/numpy/core/include
– detecting Python 3.7…
– Python 3.7 wasn’t found
– Copying /home/hld/jetson-inference/utils/python/examples/camera-viewer.py
– Copying /home/hld/jetson-inference/utils/python/examples/cuda-from-numpy.py
– Copying /home/hld/jetson-inference/utils/python/examples/cuda-to-numpy.py
– Copying /home/hld/jetson-inference/utils/python/examples/gl-display-test.py
– trying to build Python bindings for Python versions: 2.7;3.6;3.7
– detecting Python 2.7…
– found Python version: 2.7 (2.7.15+)
– found Python include: /usr/include/python2.7
– found Python library: /usr/lib/aarch64-linux-gnu/libpython2.7.so
– detecting Python 3.6…
– found Python version: 3.6 (3.6.8)
– found Python include: /usr/include/python3.6m
– found Python library: /usr/lib/aarch64-linux-gnu/libpython3.6m.so
– detecting Python 3.7…
– Python 3.7 wasn’t found
– Copying /home/hld/jetson-inference/python/examples/detectnet-camera.py
– Copying /home/hld/jetson-inference/python/examples/detectnet-console.py
– Copying /home/hld/jetson-inference/python/examples/imagenet-camera.py
– Copying /home/hld/jetson-inference/python/examples/imagenet-console.py
– Copying /home/hld/jetson-inference/python/examples/my-detection.py
– Copying /home/hld/jetson-inference/python/examples/my-recognition.py
– Copying /home/hld/jetson-inference/python/examples/segnet-batch.py
– Copying /home/hld/jetson-inference/python/examples/segnet-camera.py
– Copying /home/hld/jetson-inference/python/examples/segnet-console.py
– Configuring done
– Generating done
– Build files have been written to: /home/hld/jetson-inference/build
[ 1%] Linking CXX shared library …/aarch64/lib/libjetson-utils.so
/usr/bin/ld: cannot find -lGL
collect2: error: ld returned 1 exit status
utils/CMakeFiles/jetson-utils.dir/build.make:2627: recipe for target ‘aarch64/lib/libjetson-utils.so’ failed
make[2]: *** [aarch64/lib/libjetson-utils.so] Error 1
CMakeFiles/Makefile2:927: recipe for target ‘utils/CMakeFiles/jetson-utils.dir/all’ failed
make[1]: *** [utils/CMakeFiles/jetson-utils.dir/all] Error 2
Makefile:129: recipe for target ‘all’ failed
make: *** [all] Error 2

I don’t kown how to solve it ,I’ve written some programs on embedded MCU before,eg,FreeScale. But I’m a novice at TX2 and Ubuntu while interested in them very much.
thank you very much

I have solved it by bellow:

$sudo apt-get install mlocate
$sudo updatedb
$locate libGL.so
and it appeared :
/usr/lib/aarch64-linux-gnu/libGL.so
/usr/lib/aarch64-linux-gnu/libGL.so.1
/usr/lib/aarch64-linux-gnu/libGL.so.1.0.0

$ sudo ln -s /usr/lib/aarch64-linux-gnu/libGL.so.1.0.0

then anything is ok.