directly re-uses existing ber buf.

it's set by ldap_int_sasl_external().

Use sizeof( string ) to determine buffer size
Put authzDN in same for as used on server
(We could, just as well, set authid to "fubar" as it matters
not what it is set to)

used by the client side. Please review.

require it to only be accessible by its owner, otherwise ignore it.

propagate peer creds if no explicit PEERCRED facility exists. Works
on Solaris 8.

due to res_() routines).  Change all res_() dependent routines to
share same mutex.

Misc control cleanups (client only)

-llber is available for -llunicode.  Add -llber to ucgendat
(to pick up snprintf).