Remove redundant DEFAULT_SRC_INSTALL_EXTRA_DOCS
Remove empty categories before comitting
Remove app-random/ent

I don't know how to read the output and trust my RNG's own tests.
...or a pseudonym, full stop.
Replace LINUX_RELEASE with LINUX_KERNEL_RELEASE

There's no temporal overlap, and they're basically the same thing.

Right?
Remove now-unused pkg_setup

It dates from an age of confusion and manually created
BootLoaderSpec entries.
Never "require scm-git" twice!

It will cause scm_src_fetch_extra to loop endlessly.