https://wiki.gentoo.org/wiki/Kernel/Upgrade


      Sanitize sources

If you just want to rebuild the current kernel, you need sometimes to
sanitize the kernel sources:

|root # ||make distclean|

Interesting option. Wish it had said it would nuke my .config as well.
Just finished setting it up. Thought I'd follow the advice given before
rebuilding the kernel. Should've backed up the .config file prior to
running 'make distclean'.

Lesson learnt. :'(