Even if they're empty we want to keep these top-level directories around
as the installer has nicely created them with the correct permissions
and this avoids potentially having to use `sudo` to recreate them.
Remove broken symlinks from `/Applications` and `~/Applications` that
were previously created by `brew linkapps`, but are no longer valid
because formulae were uninstalled or the provided apps have changed.
We don't need to migrate the tapped formulae from symlink-based to
directory-based structure any more.
Instead, we add core tap install check for `brew update-report` which
will be invoked by `brew update`.
The code was sucking. To the extent that maintenance was hard. It's a lot
easier to work with code that is sensibly split at sensible boundaries. So
now it is more like that.
But the refactor is minimal. Because we don't want you to have more merge
hell than absolutely necessary.
If you merge you will need to pay attention to brew.h.rb (as it is deleted)
and bin/brew (as command logic is gone). It will be painful, but you will just
have to help git out by moving any changes around manually.
Note compatibility.rb. It ensures that any function renames or removals don't
break anything. We're pretty serious about backwards compatibility. And that's
because we encourage you to hack around with the innards. And we couldn't do
that if we would then just make stuff disappear behind your back.
