Build M1 binaries with PocketFFT (pytorch#62222)

Summary:
As MKL is only available on x86_64 platform, clone header-only PocketFFT
library and use it as FFT provider

Fixes pytorch#62107

Pull Request resolved: pytorch#62222

Reviewed By: ejguan

Differential Revision: D29938718

Pulled By: malfet

fbshipit-source-id: ac0bd98b5090d6c8a26c36c4e34a4d6e1d9f1a92

Author: malfet

.jenkins/pytorch/macos-build.sh

@@ -30,6 +30,10 @@ fi
 if [ -z "${CROSS_COMPILE_ARM64}" ]; then
   USE_DISTRIBUTED=1 python setup.py install
 else
+  pushd "${HOME}"
+  git clone https://github.com/malfet/pocketfft --depth 1 --branch cpp
+  popd
+  export POCKETFFT_HOME="${HOME}/pocketfft"
   export MACOSX_DEPLOYMENT_TARGET=11.0
   USE_DISTRIBUTED=1 CMAKE_OSX_ARCHITECTURES=arm64 USE_MKLDNN=OFF USE_NNPACK=OFF USE_QNNPACK=OFF BUILD_TEST=OFF python setup.py bdist_wheel
 fi