make "quickworld"? (like in DragonFly)

[Geert Hendrickx]

Hi, 

is there any way (or could it be implemented) to rebuild only the
changes in world and kernel sources after a cvsup?  DragonFly BSD
features "make quickworld" and "make quickkernel" which does exactly
that.  

I understand this might result in some conflicts, and DragonFly also
advises to do a full buildkernel and buildworld in case of problems.
But on the other hand, it's very frustrating to see all the stuff like
gcc, perl, sendmail, ... being recompiled just because of some minor
changes in some other, unrelated part of the OS.  And in the end, that
is exactly what make has been designed for: only rebuild the changes
(and whatever depends on that).  

Any thoughts?  

GH

PS: please CC me in reply.