I changed one .c file in /usr/src and want to rebuild world but this seem to take ages ...
-DNO_CLEANso it only rebuilds what is required to be rebuilt, instead of building everything from scratch.
-DNO_CLEANcan sometimes lead to strange problems (rare, but possible).
I'd assume this is not the only thing that can go wrong withYeah, don't use it when newvers.sh has been changed. It'll lead to some really weird version errors.
-DNO_CLEAN. Admittedly, it will work fine as a one-time solution when you really just did a trivial change