Wrapper for AMD's OpenCL FFT.
Sadly not open sourced and the library uses version tags which prevents linking it to the NVidia OpenCL library installed with their Linux driver. Since the vendor-specific part is decoupled from this, we can use AMD's OpenCL library with NVidias driver though.
With clAmdFft 1.8.291 on NVidia hardware the result is completely wrong though...