It appears that autogen.sh doesn't like es.po if it isn't mentioned in
[tinc] / po /
drwxr-xr-x   ..
-rw-r--r-- 83 .cvsignore
-rw-r--r-- 272 POTFILES.in
-rw-r--r-- 30173 nl.po
drwxr-xr-x - old