Enable fft support for mobile builds

[malfet]

Base on the conversation in #60976 (comment) it would be good to enable FFT operation support for PyTorchLite builds by default

cc @malfet @mruberry @peterbell10 @walterddr

[malfet]

I guess adding it as submodule to pytorch repo would automatically achieve this goal

[peterbell10]

Regarding #60976 (comment), there is a pocketfft github at https://github.com/mreineck/pocketfft. The one listed in the comments of that PR is NOT the original author's github.

[malfet]

@peterbell10 I don't think we can use https://gitlab.mpcdf.mpg.de/mtr/pocketfft/ in our CI/CD, as the might not be accessible enough.

[hwangjeff]

hi @malfet, have there been any new developments on this? many of torchaudio's feature extraction utilities rely on fft — enabling fft support for mobile builds by default would facilitate wider adoption of torchaudio on mobile

[peterbell10]

FFT support for mobile should be fixed in #67909 which is in the latest 1.11.0 release.