[C++][CI] homebrew-cpp fails due to avx512

[asfimport]

This has been failing for a couple of days now. See e.g. https://travis-ci.org/github/ursa-labs/crossbow/builds/721587052#L9183

In file included from /tmp/apache-arrow-20200827-98957-1ebvdk8/cpp/src/arrow/util/bpacking_avx512.cc:19:
/tmp/apache-arrow-20200827-98957-1ebvdk8/cpp/src/arrow/util/bpacking_avx512_generated.h:46:15: error: always_inline function '_mm512_set1_epi32' requires target feature 'avx512f', but would be inlined into function 'unpack1_32_avx512' that is compiled without support for 'avx512f'
  reg_masks = _mm512_set1_epi32(mask);
              ^

Could be caused by ARROW-9702?

Reporter: Neal Richardson / @nealrichardson
Assignee: Frank Du / @jianxind

PRs and other links:

• GitHub Pull Request #8071

_{Note: This issue was originally created as ARROW-9877. Please see the migration documentation for further details.}

[asfimport]

Frank Du / @jianxind:
Yes. But how can I trigger a homebrew-cpp build?

@ursabot crossbow submit homebrew-cpp ?

[asfimport]

Neal Richardson / @nealrichardson:
Yeah, close: @github-actions crossbow submit homebrew-cpp

[asfimport]

Frank Du / @jianxind:
Apple clang doesn't extract "-march=skylake-avx512" to include "-mavx512f -mavx512cd -mavx512vl -mavx512dq -mavx512bw"

[asfimport]

Neal Richardson / @nealrichardson:
Issue resolved by pull request 8071
#8071