From: Sam Ravnborg <sam@ravnborg.org>

Make the difference between 'make clean' and 'make distclean/mrproper' more
explicit.

make clean now removes all generated files except .config* and .version.
The result is much easier to understand now.

make clean deletes all generated files (except .config* and .version).
make mrproper deletes configuration and all temporary files left by patch,
editors and the like.

Example output:
> make mrproper
  CLEAN   init
  CLEAN   usr
  CLEAN   scripts/kconfig
  CLEAN   scripts
  CLEAN   .tmp_versions include/config
  CLEAN   include/asm-i386/asm_offsets.h include/linux/autoconf.h include/linux/version.h include/asm .tmp_versions
  CLEAN   .version .config

Form the list of files/directories deleted during make clean, removed all
references that is no longer relevant for the current kernel.