[ARROW-11152] [CI][C++] Fix Homebrew numpy installation on macOS builds

• Type: Bug
• Status: Resolved
• Priority: Blocker
• Resolution: Fixed
• Fix Version/s: 3.0.0
• Component/s: C++, Continuous Integration
• Labels: pull-request-available
• Assignee: Neal Richardson
• Reporter: Neal Richardson
• Created: 06/Jan/21 19:33
• Updated: 07/Jan/21 02:08
• Resolved: 07/Jan/21 02:08

Description

Numpy fails to install with homebrew because it tries to upgrade gcc and hits a brew link error. Running brew unlink gcc@8 gcc@9 before brew install could work around this.

Issue Links

• links to: GitHub Pull Request #9119