Fix the brew tests error:
InstallTests#test_a_basic_install:
FormulaUnavailableError: No available formula with the name "gcc"
Library/Homebrew/formulary.rb:231:in `get_formula'
Library/Homebrew/formulary.rb:259:in `factory'
Library/Homebrew/extend/ENV/shared.rb:287:in `gcc_version_formula'
Library/Homebrew/extend/ENV/super.rb:124:in `determine_path'
Library/Homebrew/extend/ENV/super.rb:44:in `setup_build_environment'
Library/Homebrew/build.rb:87:in `install'
Library/Homebrew/build.rb:201:in `<main>'
31e5ed28d1