option('fft',
       type: 'combo',
       choices: ['auto', 'kissfft', 'fftw', 'vdsp', 'ipp'],
       value: 'auto',
       description: 'FFT library to use. The default (auto) will use vDSP if available, KissFFT otherwise.')

option('resampler',
       type: 'combo',
       choices: ['auto', 'libsamplerate', 'speex', 'ipp'],
       value: 'auto',
       description: 'Resampler library to use. Recommended is libsamplerate. The default (auto) will use libsamplerate if available, speex otherwise.')

option('ipp_path',
       type: 'string',
       value: '',
       description: 'Path to Intel IPP libraries, if selected for any of the other options.')