https://desertbot.io/blog/how-to-cross-compile-for-raspberry-pi
PI Tools
https://github.com/raspberrypi/tools
Docker cross compile container details:
https://bitbucket.org/mitchallen/pi-cross-compile/src/master/
docker pull mitchallen/pi-cross-compile
mkdir raspberry
cd raspberry
git clone https://github.com/mitchallen/pi-hello-cross-compile.git --depth=1 hello
docker run -it -v ${PWD}/raspberry/hello:/build mitchallen/pi-cross-compile
ls ./hello/bin/hello
./hello/bin/hello
file ./hello/bin/hello
Cross Compile OpenCV for PI via Docker cross compiler
Tut:
https://solarianprogrammer.com/2018/12/18/cross-compile-opencv-raspberry-pi-raspbian/