Plugins... Nearing completion. Yay! Quite a reasonably tidy server variables declarations and implementation now. Just one variable which I may eliminate and free (potentially a few kilobytes) as it is no longer strictly necessary.
Right now, only InnoDB has been modified to take advantage of it - easily make MyISAM make use of it for it's few variables.
Need to concider splitting out more subsystems so that more globals can be removed.