What do I need?

x86/x64 machine running any OS; 4G ram, SSD, quad core (recommended),
VirtualBox or similar virtualization software (highly recommended with a minimum of 20GB hard disk space for the virtual disk image),
alternatively - Docker, systemd-nspawn or other containerization software. Using Xenial build host inside containers is highly recommended,
compilation environment is highly recommended to be Ubuntu Xenial 16.04 x64 (other releases are not officially supported but Ubuntu Trusty 14.04 x64 might still work),
installed basic system, OpenSSH and Samba (optional),
superuser rights (configured sudo or root shell).

How to start?

apt-get -y -qq install git
git clone --depth 1 https://github.com/igorpecovnik/lib
cp lib/compile.sh .
nano compile.sh # alter if necessary

Run the script

./compile.sh

Instead of editing compile.sh to set options, you can set them by supplying command line parameters to compile.sh Example:

./compile.sh BRANCH=next BOARD=cubietruck KERNEL_ONLY=yes PROGRESS_DISPLAY=plain RELEASE=jessie

Note: Option BUILD_ALL cannot be set to "yes" via command line parameter.