You can clone with
class GrowlPreHook < Hook
Growl.notify 'Building...', :title => 'Jekyll'
class GrowlPostHook < Hook
Growl.notify 'Build complete', :title => 'Jekyll'
We'd like to take advantage of Jekyll's new plugin architecture instead of maintaining a fork. Unfortunately, it's not possible to have growl notifications behave in the same way without monkey patching generator plugins.
I've pushed an experimental branch which adds pre-hook, in-hook and post-hook plugin support while preserving compatibility with existing Generators. It's mostly proof of concept, but I think it's a step in the right direction if it can be merged upstream.