gobjc-6-powerpc64-linux-gnu software package provides GNU Objective-C compiler, 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 gobjc-6-powerpc64-linux-gnu
gobjc-6-powerpc64-linux-gnu is installed in your system.
Make ensure the gobjc-6-powerpc64-linux-gnu package were installed using the commands given below,
$ sudo dpkg-query -l | grep gobjc-6-powerpc64-linux-gnu *
You will get with gobjc-6-powerpc64-linux-gnu package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Development |
| Package | gobjc-6-powerpc64-linux-gnu |
| Version | 6.1.1-9cross1 |
| Description | GNU Objective-C compiler |
| Sub Section | devel |