Packages to Install on OpenBSD for command line-based GNUstep applications

[Tito Mari Francis Escaño]

Hi,
I would like to start learning Objective-C programming by writing command
line-driven tools in Unix-like systems, in this case, particular to OpenBSD
7.5.
What should be the minimum set of packages I should install to get started?
Please advise.
Thank you.