Add commented out example Configuration section.

Because of how AC_CONFIG_FILES substitutes, this is the best we can do
because any non default configuration adds unset data otherwise.
hashmap: size hashmap bucket array dynamically

Backport some hashmap changes from systemd to ensure hashmap
dynamically allocates memory and optimizes lookup times.

Signed-off-by: Michael Ikey Doherty <michael.i.doherty@intel.com>