GitLab

This is a reland of 8e4cf155

This CL includes the following changes:
1. when fuzzing, PFFFT is compiled disabling SIMD
2. SIMD is also disabled on fuchsia and android because PFFFT only checks __arm__
3. unit test to validate the output of PFFFT (compared against that of FFTPACK)

The first change fixes the problem due to which the original CL has been reverted;
however, it makes fuzzing slower and reduces the coverage since SIMD cannot be used.

Similarly, the second change is a temporary solution to allow landing this CL.
SIMD will be re-enabled in a follow-up CL.

Original change's description:
> Add build file for PFFFT
>
> - fuzzer corpus generator and fuzzer targets
> - fftpack isolated as private test only target (only needed for the benchmark)
>
> Bug: webrtc:9577
> Change-Id: Idc904bc4b05f945a7461a14893518551bbe34b84
> Reviewed-on: https://chromium-review.googlesource.com/c/1452000
> Commit-Queue: Ale Bzk <alessiob@chromium.org>
> Reviewed-by: Nico Weber <thakis@chromium.org>
> Reviewed-by: Olga Sharonova <olka@chromium.org>
> Reviewed-by: Max Moroz <mmoroz@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#629627}

Bug: webrtc:9577
Change-Id: Icfbb4b966c3ad866e9e2970b63363e0e258b1fea
Reviewed-on: https://chromium-review.googlesource.com/c/1458076
Commit-Queue: Ale Bzk <alessiob@chromium.org>
Reviewed-by: Nico Weber <thakis@chromium.org>
Reviewed-by: Max Moroz <mmoroz@chromium.org>
Reviewed-by: Max Morin <maxmorin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#630085}