| For kernel options, I would use #ifdef clauses in code to avoid
| compiling something that people may not want ;) Be careful to set NULL
| pointers in vga structures when kernel option is disabled.

Why does scrollback need to be inside the kernel anyway?  Why not
make it a userland daemon.  A daemon has several advantages:

	Much less kernel bloat.  You don't have the code to do
	the scrolling and you don't have all the data that needs
	to be scrolled inside the kernel.

	The data will be paged in or out as needed.  You are not
	wiring down memory to track data for displays you may
	never use.

	You can easily read config files which describe which
	screens to track and what keys to use for scrolling.

Eduardo