"etcupdate extract" -- Failed to build new tree.

Hi!

"etcupdate extract" exhausts "Failed to build new tree."
Same for explicitly handling "/usr/src". "/usr/src" was pulled using "cd
/usr/src; git pull".
Searching the internet with google was not helpful.

Before building, right after:

rm -rf /usr/src
mkdir /usr/src
git clone https://github.com/freebsd/freebsd-src.git /usr/src
etcupdate extract
-> Failed to build new tree.

As far as all docs I've found tell, this is expected to work without flaws.
Any ideas?

-- 
Thomas