This avoids can avoid UID/EUID related issues with Ruby scripts passed
over `stdin` clashing with Ruby security features.
It's also just a bit nicer to have Ruby scripts in files instead.
While we're here:
- refactor some shared logic into a new `setup-gem-home-bundle-gemfile`
function in `ruby.sh`
- do some general cleanup of `lock.sh`
- prioritise `flock` over `python` in `lock.sh`
If you're e.g. running Homebrew over `sudo`: shelling out to `whoami`
is less effective than just telling people which user you're running
as when we run the check.
Fixes (on centos6):
which: no flock in (/home/linuxbrew/.linuxbrew/bin:/home/linuxbrew/.linuxbrew/sbin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin)
Ruby first gained flock in 1.8.7, which is a problem since we're using
this lock utility in `vendor-install` in order to install a newer Ruby.
Fortunately, Python 2.3(!) has flock support.
Since #292, HOMEBREW_CACHE was moved to a per-user directory. This makes
it unsuitable to store global lock files on multiple users environment.
Therefore, introducing a global lock directory `/Library/Lock.d` to
store lock files from formula lockers as well as `brew update`.
