This caused build problems with KDE which should now be fixed.
Updating KDE packages should be much faster as a result and less
patching required upstream.
This patch has been applied upstream already to the KDE repository
so will not be needed for the next release of automoc4.
brewkit.rb changes ENV destructively, so lets not do that everytime a formula
is required. Now it's possible for other tools to require a formula
description without worrying about side-effects.