initdb when data/ folder has mount points

Hi,

v9.6.6

Apparently, initdb assumes that data/ is one big mount point.  However, we have four mount points:
/var/lib/pgsql/9.6/data/backup
/var/lib/pgsql/9.6/data/base
/var/lib/pgsql/9.6/data/pg_log
/var/lib/pgsql/9.6/data/pg_xlog

They are all empty.  How do I convince it to ignore the fact that the directories exist?

Thanks