* windows-nat.c (AdjustTokenPrivileges): Implement macro wraparound for

* windows-nat.c (AdjustTokenPrivileges): Implement macro wraparound for
dynamically loaded function.
(LookupPrivilegeValueA): Ditto.
(OpenProcessToken): Ditto.
(AdjustTokenPrivileges): Rename and define placeholder for address of
dynamically loaded function.
(LookupPrivilegeValueA): Ditto.
(OpenProcessToken): Ditto.
(set_process_privilege): Remove check for loaded functions.
(bad_OpenProcessToken): Define.
(_initialize_loadable): Load token functions from advapi here, setting
OpenProcessToken function to a dummy static function which always return error
if OS doesn't support this functionality.