It appears that autogen.sh doesn't like es.po if it isn't mentioned in
[tinc] / doc / sample-config /
drwxr-xr-x   ..
drwxr-xr-x - hosts
-rw-r--r-- 48 rsa_key.priv
-rw-r--r-- 223 tinc-down
-rw-r--r-- 559 tinc-up
-rw-r--r-- 723 tinc.conf