565987 - redhat-ds-base fails to build due to undefined struct
    st_size and nsldapi_build_control et al. in ldclt.c
    
    https://bugzilla.redhat.com/show_bug.cgi?id=565987
    
    Fix Description:
    1. stat: sys/types.h and sys/stat.h need to be included.
    2. nsldapi_build_control: duplicated nsldapi_build_control from
       the mozldap c library.
    3. added the sub value [=deref:attr] of deref to the usage.
    4. allow -e deref without the sub value.  It used to be allowed,
       but it was forbidden by the previous change.