This routine adds an object identifier to an object identifier
set. It is intended for use in conjunction with gss_create_empty_oid_set when
constructing a set of mechanism OIDs for input to gss_acquire_cred.
The oid_set argument must refer to an
OID-set that was created by GSSAPI (for example, a set returned
by gss_create_empty_oid_set). GSSAPI creates
a copy of the member_oid and inserts this
copy into the set, expanding the storage allocated to the OID-set's
elements array if necessary. The routine may add the new member
OID anywhere within the elements array; if the member_oid is
already present, the oid_set remains unchanged.