Steps to reproduce the issue

$ spack install -v openblas

Error messages are shown here.

Information on your system

• Spack: 0.15.4-947-1aceb38b8
• Python: 3.8.5
• Platform: darwin-macos-skylake
• Version: 11.0 beta Big Sur

• packages.yaml here

Additional information

• spack-build-out.txt
• spack-build-env.txt

General information

• I have run spack debug report and reported the version of Spack/Python/Platform
• I have run spack maintainers <name-of-the-package> and @mentioned any maintainers
• I have uploaded the build log and environment files
• I have searched the issues of this repo and believe this is not a duplicate