Allow _gss_string_to_oid() without HAVE_DLOPEN
This function became used outside the protection of
HAVE_DLOPEN (which Samba sets) with:
commit
5966c00701d9045fb5440a0d15c14a02cfd99f01
Author: Luke Howard <lukeh@padl.com>
Date: Sun Aug 8 10:34:28 2021 +1000
gss: add gss_mg_name_to_oid internal API
Add a new function for future internal use, gss_mg_name_to_oid(), which takes
either a dot-separated OID or a "short" mechanism name (such as
"sanon-x25519"), and returns a mechanism OID.
Signed-off-by: Andrew Bartlett <abartlet@samba.org>