libgfortran not found on GitHub Actions/macos-10.15/20200707.3

[termoshtt]

Maybe some undocumented update happens actions/runner-images@3d7f736

[termoshtt]

https://github.com/rust-ndarray/ndarray-linalg/runs/873414071 (in #221)

  = note: ld: warning: directory not found for option '-L/usr/local/opt/gcc/lib/gcc/9'
          ld: library not found for -lgfortran
          clang: error: linker command failed with exit code 1 (use -v to see invocation)

Install directory seems to be changed

[termoshtt]

One says gfortran exists, and another says gfortran does not exist. macOS runner is completely broken. I never use them https://github.com/rust-ndarray/ndarray-linalg/runs/1105321333