gdc-multilib software package provides D compiler (language version 2) (multilib files), 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 gdc-multilib
gdc-multilib is installed in your system.
Make ensure the gdc-multilib package were installed using the commands given below,
$ sudo dpkg-query -l | grep gdc-multilib *
You will get with gdc-multilib package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Development |
| Package | gdc-multilib |
| Version | 4:6.1.1-1 |
| Description | D compiler (language version 2) (multilib files) |
| Sub Section | devel |