Install WireGuard on Raspberry Pi 1, 2 (not v1.2), Zero, Zero W

On these RPi's you need to compile manually. Why? The Raspberry Pi's CPU doesn't have some of the features of the armhf arch in Debian, if you download and install the armhf package, it will crash (Segmentation fault).

1, Install kernel headers, git and required components

pi@raspberrypi:~ $ sudo apt-get install raspberrypi-kernel-headers libmnl-dev libelf-dev build-essential git

2, Clone WireGuard repository and compile it

pi@raspberrypi:~ $ git clone https://git.zx2c4.com/WireGuard
pi@raspberrypi:~ $ cd WireGuard/src
pi@raspberrypi:~/WireGuard/src $ make
pi@raspberrypi:~/WireGuard/src $ sudo make install

If anytime you want to upgrade WireGuard, run:

pi@raspberrypi:~ $ cd WireGuard/
pi@raspberrypi:~/WireGuard $ git pull
pi@raspberrypi:~/WireGuard $ cd src/
pi@raspberrypi:~/WireGuard/src $ make
pi@raspberrypi:~/WireGuard/src $ sudo make install

Done.