Error Building on Mac M1

[ellieyhcheng]

I ran into errors building on Mac M1 where owl can't be installed. The work-around exists in this PR but it hasn't been merged yet. So until then, running this to install owl will allow ProbZelus to build successfully:

opam pin -n git+https://github.com/mseri/owl.git#arm64 --with-version=1.1.0
PKG_CONFIG_PATH="/opt/homebrew/opt/openblas/lib/pkgconfig" opam install owl.1.1.0

[gbdrt]

Thanks a lot for documenting this.

Unfortunately owl is pretty unstable (even on Intel).
Hopefully this will be resolved in the next versions.