I was trying to debug the problem myself and it seems the SSL initialization fails in svrcore_setup function in ldap/servers/slapd/ssl.c. The code there tries to call SVRCORE_CreateStdSystemdPinObj or SVRCORE_CreateStdPinObj functions from libsvrcore0 library based on --with-systemd configure option, so I guess it's SVRCORE_CreateStdSystemdPinObj and the function fails. I've tried to enable debug for libsvrcore0 to find where exactly it fails but without success.
-- Michal Kašpar
