DEF_RUN_DIR is defined based on SYSRUNDIR which is itself set to localstatedir.

In the Debian package, I've set this to /run but it does look strange to set --localstatedir when there is also a --runstatedir configure variable:

--localstatedir=DIR     modifiable single-machine data [PREFIX/var]
--runstatedir=DIR       modifiable per-process data [LOCALSTATEDIR/run]

It doesn't look like runstatedir is used anywhere and so it doesn't matter that it ends up being set to a non-sensical value (/run/run), but perhaps DEF_RUN_DIR should use that instead of localstatedir?