export NDK=/home/user/Android/Sdk/ndk/21.0.6113669/
export ABI=arm64-v8a
export MINSDKVERSION=21
cmake \
    -DCMAKE_TOOLCHAIN_FILE=$NDK/build/cmake/android.toolchain.cmake \
    -DANDROID_ABI=$ABI \
    -DANDROID_PLATFORM=android-$MINSDKVERSION \
    CMakeLists.txt
make