Specify the callback function to use in the server for validating a
user via the SECURID mechanism. The function should return
GSASL_OK if user authenticated successfully,
GSASL_SECURID_SERVER_NEED_ADDITIONAL_PASSCODE if it wants another
passcode, GSASL_SECURID_SERVER_NEED_NEW_PIN if it wants a PIN
change, or an error. When (and only when)
GSASL_SECURID_SERVER_NEED_NEW_PIN is returned, suggestpin can be
populated with a PIN code the server suggests, and suggestpinlen
set to the length of the PIN. The function can be later retrieved
using gsasl_server_callback_securid_get().
DEPRECATED
This function is part of the old callback interface.
The new interface uses gsasl_callback_set() to set the application
callback, and uses gsasl_callback() or gsasl_property_get() to
invoke the callback for certain properties.