adduser gnunet gnunet
to
adduser --system --home "/var/lib/gnunet" --group gnunet
In sync with what is recommended later on in the README (use of /var/lib),
as suggested by adfeno in freenode.
$ export GNUNET_PREFIX=/usr/local/lib # or other directory of your choice
# addgroup gnunetdns
-# adduser gnunet gnunet
+# adduser --system --home "/var/lib/gnunet" --group gnunet
# ./configure --prefix=$GNUNET_PREFIX/.. --with-extractor=$LE_PREFIX
$ make
# make install