AVX2 bug in Docker Desktop on macOS

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See OpenBLAS issue #2244: "FATAL ERROR" messages building or running OpenBLAS v0.3.7 in Docker on macOS.

• Building OpenBLAS in Docker Desktop on macOS fails the self-test part of its build.
  • This is Docker Desktop 2.1.0.1 (37199), Engine 19.03.1, on macOS 10.14.6.
  • I don't know how to tell what version of xhyve it uses.
• Building OpenBLAS directly on macOS works fine.
• Building OpenBLAS in Docker on Linux works fine.
• Adding NO_AVX2=1 to the make step avoids this failure -- with a performance penalty.

The OpenBLAS team (@brada4, @martin-frbg) concludes that xhyve has a bug in AVX2 support that will break fast math libraries, video codecs, and everything else compiled with -march=native:

To serve OpenBLAS it is sufficient to mask out any CPUID bits with the effect on CPU registers exceeding original AVX, an extension they seem to support.

[brada4]

The fatal errors are encountered in comparisons after math accuracy tests, not the compilation itself, because of what seems like AVX2 state being corrupt at low level behind the scenes.