Matthew Dillon has committed code that makes a ‘make buildkernel/nativekernel‘ remove the obj heirarchy before starting; this solves the occasional out-of-date file problem during a system build. Also, ‘make quickkernel‘ is now possible, so if you are building a system with source that has not been updated since the last build, you can save time and use the ‘quickworld‘ and ‘quickkernel‘ targets instead of ‘buildworld‘ and ‘buildkernel‘.