wxWidgets - wxWidgets: Cross-Platform GUI Library
PortAudio - PortAudio is a cross platform, open-source, audio I/O library.
Electron - Build cross platform desktop apps with web technologies
OpenAL Soft - OpenAL Soft is an LGPL-licensed, cross-platform, software implementation of the OpenAL 3D audio API.
GTK - GTK+ is a multi-platform toolkit for creating graphical user interfaces.
JUCE - JUCE is a wide-ranging C++ class library for building rich cross-platform applications and plugins...