Install on Debian Stretch

sudo apt install lirc

Enable LIRC & specify pins

# sudo echo "lirc_dev" >> /etc/modules
# sudo echo lirc_rpi gpio_in_pin=20 gpio_out_pin=16 >> /etc/modules
sudo echo dtoverlay=gpio-ir,gpio_pin=20,gpio_pull=up >> /boot/config.txt

Find and alter following lines in /etc/lirc/lirc_options.conf

driver = default
device = /dev/lirc0

Paste following code into file /etc/lirc/hardware.conf

########################################################
LIRCD_ARGS="--uinput --listen"
LOAD_MODULES=true
DRIVER="default"
DEVICE="/dev/lirc0"
MODULES="lirc_rpi"

LIRCD_CONF=""
LIRCMD_CONF=""
########################################################

Reboot to apply changes

sudo reboot

Enable LIRC service

sudo systemctl enable lircd.service && sudo systemctl start lircd.service
sudo systemctl status lircd.service