The “McLaren Synth Kit” is an Objective-C framework for using MIDI and Audio on Linux computers with the GNUstep programming environment. It is distributed as a project including libraries, headers and example programs at https://github.com/mclarenlabs/McLarenSynthKit. You can use it to experiment with sound synthesis for your own personal projects. The project is designed to provide ready-to-compile examples after you clone the repo.

Working with sound is a delicate endeavor. The Synth Kit does a lot of the low-level work of opening devices, managing an audio thread and copying MIDI events to and from dispatch queues. This leaves the audio programmer free to think about designing sounds as a graph of processing units, called Voices.
Standard Voices in the Synth Kit provide envelopes and oscillators of various types, filters and a reverb algorithm. Using the features of modern Objective-C (blocks, ARC and dispatch queues) the Synth Kit makes programming sounds easy, or at least “easier.”
There is evolving documentation describing the design goals and use of the project here:
https://mclarenlabs.github.io/McLarenSynthKit/
and the source code repository is here:
https://github.com/mclarenlabs/McLarenSynthKit/
There’s some other fun stuff in the project repository too. One is a document describing how to use Visual Studio Code (https://code.visualstudio.com) for programming in Objective-C with the clangd (clang-daemon) extension for intelligently creating code. All in all, it’s a very nice audio programming environment.