After all these years installing from source, I’m giving Dahdi package installation a try on a recent Stretch box.
Note: Sangoma’s USBfxo is a low-cost development tool kit, ideal for those just getting started with Asterisk® or those who just want a simple external solution. The USBfxo is easy to install. There is no need to open up the computer to insert an interface card. Simply plug it in, and set up your Asterisk system; configure Sangoma’s Wanpipe® drivers, as you would with any Sangoma card, and you’re set to go. You can even connect multiple USBfxos in one system. TheUSBfxo fully supports Asterisk on Linux systems and includes Zaptel/DAHDI drivers.
Google over the web, I didn’t find too many doc on this topic.
1. Is this one  up-to-date? Reading Stretch I would say a single asterisk-dahdi would be enough to install asterisk dahdi and libpri.
2. On my box, the following fails. What would you suggest ? Re-base everything on Jessie ? apt-get install linux-headers-`uname -r`
3. How is dahdi started-stopped in Stretch ? (I can’t find any /etc/init.d/dahdi file after apt-get install asterisk-dahdi).