fmdemod implements a first pass at the functionality provided by rtl-fm, supporting demodulation of WBFM stations broadcasting at 87.9MHz. It uses basic dphase/dt demodulation, an audio bandpass implemented via a fast overlap-scrap FIR filter, with kissfft, sdl, and pulseaudio helping move bits around.
spectrosearch implements a GPU accelerated spectrum waterfall using opencl, opengl, and glfw.
These were intended as a proof of concept - I'll readily accept criticisms, suggestions, bug reports, and patches.