cl-cffi software package provides The Common Foreign Function Interface for Common Lisp, you can install in your Debian 9 (Stretch) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install cl-cffi
cl-cffi is installed in your system.
Make ensure the cl-cffi package were installed using the commands given below,
$ sudo dpkg-query -l | grep cl-cffi *
You will get with cl-cffi package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Lisp |
| Package | cl-cffi |
| Version | 1:0.17.1-2 |
| Description | The Common Foreign Function Interface for Common Lisp |
| Sub Section | Lisp |