The macOS-10.15 environment is deprecated and will be unsupported on 2022-12-01. Homebrew packages are already not available any more.

• https://github.com/actions/virtual-environments
• https://github.com/actions/virtual-environments/blob/main/images/macos/macos-12-Readme.md
• https://github.com/actions/virtual-environments/blob/main/images/macos/macos-11-Readme.md:
• https://github.com/actions/virtual-environments/blob/main/images/macos/macos-10.15-Readme.md:

There's no macOS 13 environment yet.

Possible follow-up:

• Add variants that test with an actual XCode installation (not XCode CLT) because the SDK paths are different, and there may be other subtle differences. GH Actions install location: see https://github.com/actions/virtual-environments/blob/main/images/macos/macos-11-Readme.md#xcode

Depends on #33788

CC: @culler @dimpase @vbraun

Component: porting

Author: Matthias Koeppe

Branch/Commit: f185d68

Reviewer: Dima Pasechnik

Issue created by migration from https://trac.sagemath.org/ticket/32570