The attached patch includes prototype definitions which are required for implementing and interfacing with SSP/APs (Security Support Provider/Authentication Package[s]).
Examples for builtin SSP/AP in Windows are kerberos and msv1_0. One needs these interfaces in order to implement other authentication mechanizems such as NIS+, smartcard or biometric or all other crazy things.
The prototypes may differ a little from the ones in PlatformSDK, as I've not checked against it. In another words, it is provided under the usual no warranty disclaimer.