Rather than relying on a `HOMEBREW_FORCE_BOTTLE` variable (which ends up doing silly things like forcing bottle usage even when options are provided) instead handle this at the `or_later` bottle detection level so on prerelease versions of macOS any bottle looks like an `or_later` bottle (unless various environment variables are set). Fixes issues noted in: https://github.com/Homebrew/brew/pull/4520#issuecomment-407229605
Library
This directory contains all the code run by the official brew and brew cask commands in Homebrew and all formulae (package descriptions) in taps (repositories containing formulae) in Taps subdirectories.